Systems and methods for adjusting the maximum transmission unit for encrypted communications

ABSTRACT

The present invention is generally directed towards a remote access architecture for providing peer-to-peer communications and remote access connectivity. In one embodiment, the remote access architecture of the present provides a method for establishing a direct connection between peer computing devices via a third computing device, such as a gateway. Additionally, the present invention provides the following techniques to optimize peer-to-peer communications: 1) false acknowledgement of receipt of network packets allowing communications via a lossless protocol of packets constructed for transmission via a lossy protocol, 2) payload shifting of network packets allowing communications via a lossless protocol of packets constructed for transmission via a lossy protocol, 3) reduction of packet fragmentation by adjusting the maximum transmission unit (MTU) parameter, accounting for overhead due to encryption, 4) application-aware prioritization of client-side network communications, and 5) network disruption shielding for reliable and persistent network connectivity and access.

RELATED APPLICATIONS

This present application claims priority to U.S. Provisional PatentApplication No. 60/590,837, entitled “Ad Hoc Distributed Networks AndRemote Access Architecture”, filed Jul. 23, 2004, and U.S. ProvisionalPatent Application No. 60/601,431, entitled “System And Method ForAssuring Redundancy In Remote Access Solution”, filed Aug. 13, 2004, andU.S. Provisional Patent Application No. 60/607,420, entitled “VirtualNetwork Bridging”, filed Sep. 3, 2004, and U.S. Provisional PatentApplication No. 60/608,814, entitled “System And Method For AssuringRedundancy In Remote Access Solution”, filed Sep. 10, 2004, all of whichare incorporated herein by reference.

TECHNICAL FIELD

The invention generally relates to optimizing peer-to-peer networkcommunications, and in particular, to techniques for reducing packetfragmentation by reducing the maximum transmission unit to account forencryption overhead.

BACKGROUND INFORMATION

Communications over a network between two computers, for example aclient and a server, can be implemented using a variety of knowncommunication protocols and encryption, such as SSL, may be used toprovide secure network communications. Although the communication issecure, the encryption of the network traffic increases the size of thenetwork packets, which can cause the packet payload to become too largefor a single packet. This can result in packet fragmentation, causingmore overhead for communication processing. Techniques for adjusting themaximum size of a packet to account for encryption overhead would beuseful.

SUMMARY OF THE INVENTION

The present invention is generally directed towards a remote accessarchitecture for providing peer-to-peer communications and remote accessconnectivity. In one embodiment, the remote access architecture of thepresent invention provides a method for establishing a direct connectionbetween peer computing devices via a third computing device, such as agateway. Additionally, the present invention provides various techniquesfor optimizing peer-to-peer communications, including real-timecommunications such as voice over internet protocol (VoIP) signaling andmedia, video, and other real-time data applications such as webcollaboration, screen or desktop sharing, and instant messaging. Thepresent invention provides the following peer to peer optimizationtechniques: 1) false acknowledgement of receipt of network packetsallowing communications via a lossless protocol of packets constructedfor transmission via a lossy protocol, 2) payload shifting of networkpackets allowing communications via a lossless protocol of packetsconstructed for transmission via a lossy protocol, 3) reduction ofpacket fragmentation by adjusting the maximum transmission unit (MTU)parameter, accounting for overhead due to encryption, 4)application-aware prioritization of client-side network communications,and 5) network disruption shielding for reliable and persistent networkconnectivity and access, such as for mobile computing.

In one aspect, the present invention relates to a method forestablishing a peer-to-peer communication session between a firstcomputing device on a first network and a second computing device on asecond network. The first network may be disconnected from and notroutable to the second network. The method includes establishing, by thefirst computing device, a first tunneling session with a third computingdevice, and establishing, by the second computing device, a secondtunneling session with the third computing device. The third computingdevice may be a gateway, such as an SSL VPN gateway. The first computingdevice initiates a communication session to the second computing devicevia the third computing device, such as via a signaling protocol. Aserver receives a signal to establish the initiated communicationsession, and the server communicates to the first computing device afirst network address comprising a network address of the secondcomputing device associated with the second tunneling session. The firstcomputing device communicates a request to initiate a connection withthe second computing device using the first network address. The methodfurther includes intercepting, by the third computing device, therequest, and providing the first computing device a second networkaddress for the second computing device. The second network addressidentifies a public network address associated with the second computingdevice. The third computing device communicates a request to the secondcomputing device to allow a connection from the first computing deviceusing the second network address, such as via a swimmer sessiontraversing a firewall.

In one embodiment of the present invention, the first tunneling sessionor the second tunneling session is established using a Secure SocketLayer or a virtual private network The third computing device may be aremote access gateway. In another embodiment, the second computingdevice is located behind a firewall associated with the second networkaddress.

In another embodiment, the method of the present invention includesproviding, by the third computing device, the second network address tothe first computing device by communicating an out of band signal to thefirst computing device via the first tunneling session. In an additionalembodiment, the method of includes providing, by the second computingdevice, a forward hole in a firewall for the first computing device tocommunicate to the second computing device using the second networkaddress.

In a further embodiment of the present invention, the third computingdevice communicates a key to the first computing device and the secondcomputing device. The first computing device and the second computingdevice may exchange keys. Additionally, the first and second computingdevice may check that the key received from the other computing devicematches before transmitting data to the other computing device.

In some embodiments of the present invention, the method associates afirst telecommunication device with the first computing device, andassociates a second telecommunication device with the second computingdevice. The first telecommunication device or the secondtelecommunication device may include a software component or a hardwarecomponent, such as a hard or soft VoIP telephone. In one embodiment, themethod of the present invention includes establishing atelecommunication session between the first telecommunication device andthe second telecommunication device via the connection between the firstand second computing devices. The first telecommunication device and thesecond telecommunication device may communicate over thetelecommunication session without traversing the third computing device.

In another embodiment of the present invention, the method communicatesa remote display protocol via the connection between the first computingdevice and the second computing device. The remote desktop protocol mayinclude the Independent Computing Architecture protocol or the RemoteDesktop Protocol. In yet a further embodiment, the method may includesharing a screen view or screen data of the first computing device withthe second computing device via the connection.

In one aspect, the present invention relates to a method performed in agateway for establishing a peer-to-peer communication session between afirst computing device on a first network and a second computing deviceon a second network. The first network may be disconnected from and notroutable to the second network. The method includes establishing a firsttunneling session with the first computing device on a first network,and establishing a second tunneling session with the second computingdevice on the second network. The gateway receives a request by thefirst computing device to initiate a communication session with thesecond computing device. The first computing device provides a firstnetwork address for contacting the second computing device. The firstnetwork address identifies a network address of the second computingdevice associated with the second tunneling session. The gatewayreceives a request by the first computing device to initiate aconnection with the second computing device using the first networkaddress, intercepts the request to initiate the connection, and providesthe first computing device a second network address for the secondcomputing device. The second network address identifies a public networkaddress associated with the second computing device. The gatewaycommunicates to the second computing device a request to allow theconnection from the first computing device to the second computingdevice using the second network address, such as via a swimmer sessiontraversing a firewall.

In one embodiment, the first tunneling session or the second tunnelingsession via the gateway includes a Secure Socket Layer or a virtualprivate network. In another embodiment, the second computing device islocated behind a firewall associated with the second network address. Ina further embodiment, the method of the present invention provides thesecond network address to the first computing device by communicating anout of band signal to the first computing device via the first tunnelingsession. Additionally, the gateway may communicate a key to the firstcomputing device and to the second computing device.

In another aspect, the present invention is related to a system forestablishing a peer-to-peer communication session between a firstcomputing device on a first network and a second computing device on asecond network via a third computing device. The first network may bedisconnected from and not routable to the second network. The systemincludes a first computing device on the first network, and a secondcomputing device on the second network. A third computing deviceestablishes a first tunneling session with the first computing deviceand a second tunneling session with the second computing device. Thesystem also includes a server accessible via the third computing device.In operation of the system, the server communicates via the thirdcomputing device to the first computing device a first network addressidentifying a network address of the second computing device associatedwith the second tunneling session. The first computing devicecommunicates via the third computing device a first request to initiatea connection with the second computing device using the first networkaddress. The third computing device intercepts the first request, andprovides the first computing device a second network address for thesecond computing device. The second network address identifies a publicnetwork address associated with the second computing device. The thirdcomputing device communicates a second request to the second computingdevice to allow a connection from the first computing device using thesecond network address.

In one embodiment of the system, the first tunneling session or thesecond tunneling session includes a Secure Socket Layer or a virtualprivate network. Furthermore, the third computing device may be a remoteaccess gateway, such as an SSL VPN gateway. In another embodiment of thesystem, the second computing device is located behind a firewallassociated with the second network address.

In an additional embodiment of the present invention, the thirdcomputing device provides the second network address to the firstcomputing device by communicating an out of band signal via the firsttunneling session, such as via an out of band TLS session. In oneembodiment, the second computing device provides a forward hole in afirewall for the first computing device to communicate to the secondcomputing device using the second network address.

In a further embodiment of the system of the present invention, thethird computing device communicates a key to the first computing deviceand the second computing device. The first computing device and thesecond computing device may exchange keys. Additionally, the first andsecond computing device may check that the key received from the othercomputing device matches before transmitting data.

In some embodiments of the present invention, the system includes afirst telecommunication device associated with the first computingdevice, and a second telecommunication device associated with the secondcomputing device. The first telecommunication device or the secondtelecommunication device may include a software component or a hardwarecomponent, such as a hard or soft VoIP telephone. In one embodiment, thesystem of the present invention includes establishing atelecommunication session between the first telecommunication device andthe second telecommunication device via the connection between the firstand second computing devices. The first telecommunication device and thesecond telecommunication device may communicate over thetelecommunication session without traversing the third computing device.

In another embodiment of the present invention, the first computingdevice and the second computing device communicate a remote displayprotocol via the connection. The remote desktop protocol may include theIndependent Computing Architecture protocol or the Remote DesktopProtocol. In yet a further embodiment, the first computing device mayshare a screen view or screen data with the second computing device viathe connection.

In another aspect, the present invention is related to a method forcommunicating via a lossless protocol a packet constructed to betransmitted via a lossy protocol. The method may be performed in one ormore electronic devices, such as in a system, and by any suitable meansand mechanisms. The method includes establishing a connection between afirst computing device and a second computing device via a losslessprotocol. In some embodiments, the second computing device may be agateway, such as an SSL VPN gateway. The first computing device detectsa lossless protocol packet comprising a payload having one or morepackets constructed in accordance with a lossy protocol. The firstcomputing device communicates a false acknowledgement of receipt of thelossless protocol packet to the first computing device and/or the secondcomputing device. The false acknowledgement of receipt of the losslessprotocol packet prevents employing the reliability algorithms andmechanisms of the lossless protocol. The first computing devicecommunicates the lossless protocol packet to the second computingdevice. In some embodiments, the false acknowledgement of receipt of thelossless protocol packet is communicated prior to communicating thelossless protocol packet.

In one embodiment, the method of the present invention includesencrypting, by the first computing device, the one or more packets usinga key. In some embodiments, the encryption key may be provided to thefirst computing device via an out of band transport security layersession between the first computing device and the second computingdevice. In a further embodiment, the method encrypts the one or morepackets on a packet by packet basis.

In another embodiment of the method of the present invention, inresponse to receiving the false acknowledgement of receipt of thelossless protocol packet by the first computing device and/or the secondcomputing, the first computing device and/or the second computingprevents executing an operation associated with providing a losslesscharacteristic of the lossless protocol. In one embodiment, the losslessprotocol is a transport control protocol. In a further embodiment, themethod of the present invention prevents the network stack of the firstcomputing device and/or the second computing device from executing oneor more of the following in connection with the lossless protocol: 1) aretransmit, 2) an ordering, 3) a flow control algorithm, 4) a naple'salgorithm, and 5) a sliding window algorithm.

In one embodiment, the lossy protocol includes a user datagram protocol.In another embodiment, the method includes communicating, by the firstcomputing device, the lossless protocol packet via a secure socket layeror a transport security layer tunnel to the second computing device.

In another embodiment, the one or more packets of the payload comprisesa real-time protocol. In an additional embodiment, the method includescommunicating by the first computing device one of real-time voice,audio, or data to the second computing device via the one or morepackets.

In one aspect, the present invention relates to a method fortransmitting packets from an application using an unreliable transportprotocol over a TCP connection. The method includes receiving, at afirst device, a first packet to be transmitted using an unreliabletransport protocol, and creating a first TCP packet including a firstpayload of the received first packet and a first TCP header ofinformation associated with a TCP connection established between thefirst device and a second device. The first device transmits the firstTCP packet to the second device. The method further includes receiving,at the first device, a second packet to be transmitted using anunreliable transport protocol, and creating a second TCP packetincluding a second payload of the received second packet and the firstTCP header information. Before receipt of an acknowledgement of thereceipt of the first payload from the second device, the first devicetransmits the second TCP packet to the second device.

In one embodiment, the method of the present invention establishes theTCP connection with a port number associated with the unreliabletransport protocol. In another embodiment, the method includesdynamically determining, by the first device, the first TCP packet andsecond TCP packet comprise an unreliable transport protocol. In someembodiments, the unreliable transport protocol is UDP.

In an additional embodiment, the method includes receiving the first TCPpacket and second TCP packet on the first device by intercepting thefirst TCP packet and second TCP packet using a packet capturingmechanism. In some embodiments, the method establishes by the firstdevice, the TCP connection with a VPN gateway device. In otherembodiments, the method includes establishing peer-to-peercommunications between the first device and the second device via theTCP connection. In another embodiment of the present invention, themethod includes encrypting, by the first device, the first and secondTCP packets, and decrypting, by the second device, the encrypted firstand second TCP packets.

In another aspect, the present invention relates to a method fortransmitting packets from an application using an unreliable transportprotocol over a TCP connection. The method includes intercepting, at asecond device, a first TCP packet created on a first device and receivedon the second device. The first TCP packet includes a first payload of afirst packet generated by an application using an unreliable protocoland a first TCP header of information associated with a TCP connectionestablished between the first device and the second device. Theintercepting of the method occurs before the first TCP packet isprovided to a TCP stack on the second device. The method includesidentifying, responsive to the TCP header of information, that the firstpayload is a packet generated by an application using an unreliabletransport protocol, stripping the TCP header of information from thefirst TCP packet, and forwarding the first payload to an applicationusing the unreliable data protocol.

In one embodiment, the unreliable protocol is UDP. In anotherembodiment, the step of identifying comprises identifying that the TCPheader information includes a port number associated with the unreliabletransport protocol. In some embodiments, the method includesintercepting, by the second device, the first TCP packet using a packetcapture driver.

In some embodiments, the first device is a client device and the seconddevice is a VPN gateway. Additionally, the method of the presentinvention includes performing Network Address Translation (NAT) on thesecond device prior to forwarding the first payload to the application.

In a further aspect, the present invention relates to a system fortransmitting packets from an application using an unreliable transportprotocol over a TCP connection. The system includes a first device and asecond device. The first device has an application that generates afirst and second packet. The first and second packet are intended to betransmitted using an unreliable transport protocol. The first devicealso has a filter process and a tunneling process. The filter processintercepts the first and second packets from the application andforwards the intercepted packets to the tunnel process. The tunnelprocess requests the opening of a TCP connection between the firstdevice and a second device. The request to open the TCP connectionindicates to the first and second device that the TCP connection willtransport packets intended to be transmitted with an unreliabletransport protocol. The tunnel process forwards the first and secondpackets as payloads in a first and second TCP packet to the seconddevice. The tunnel process sends the second TCP packet after sending thefirst TCP packet and prior to receiving an acknowledgement for the firstTCP packet.

The second device of the system of the present invention is incommunication with the first device. The second device has second filterprocess and tunneling process. The second tunnel process opens the TCPconnection requested by the first device, and identifies and forwardsthe source address of the TCP connection to the second filter process.The second filter process intercepts packets from the applicationreceived at the second device with the TCP connection source address ina header. The second filter process strips the TCP header from thereceived packets and forwards the stripped packets to an intendeddestination, and circumventing the TCP/IP stack on the second device.

In one embodiment of the system of the present invention, the filterprocess on the first device and/or the second filter process of thesecond device is a packet capture driver. In some embodiments, the firstdevice is a client device and the second device is a VPN gateway device.In one embodiment, the unreliable data protocol is UDP.

In another embodiment, the system also includes a third device to whichthe stripped packets are transmitted. Additionally, the second devicemay further include a Network Address Translation (NAT) table used toperform network address translation prior to transmitting the strippedpackets to the third device.

In a further aspect, the present invention is related to a method foradjusting the maximum transmission unit of a secure networkcommunication to reduce network fragmentation. The method may beperformed in one or more electronic devices, such as in a system, and byany suitable means and mechanisms. The method includes establishing asession between a first computing device and a second computing device.The session may established by an agent of the first computing device.The first computing device has a first network stack. The methoddetects, by the first computing device, a network packet having anencrypted payload, and determines a setting for a maximum transmissionunit parameter of the first network stack to reduce the maximumtransmission unit size by at least a size associated with the encryptedportion of the payload. The method alters the maximum transmission unit(MTU) parameter of the first network stack to the determined setting. Assuch, the reported MTU parameter is reduced to account for theencryption.

In one embodiment, the method of the present invention includescommunicating the network packet via a secure socket layer or atransport layer security tunnel to the second computing device. Thesecond computing device may be a gateway, such as an SSL VPN gateway. Inanother embodiment, the payload comprises a real-time protocol.

Additionally, in one embodiment, the method may further comprisealtering the maximum transmission unit parameter via a network driverinterface specification (NDIS) level mechanism of the first networkstack In another embodiment, the method determines the setting of themaximum transmission unit parameter dynamically per session between thefirst computing device and the second computing device. In oneembodiment, the agent of the first computing device communicates via anIOCTL application programming interface to the first network stack toalter the maximum transmission unit parameter to the determined setting.

In some embodiments, the method of the present invention establishes thesession between the first computing device and the second computingdevice via a gateway. In other embodiments, the method communicates bythe first computing device real-time voice, audio, or data to the secondcomputing device via the payload of the network packet. In yet anotherembodiment, the method may include communicating a false acknowledgementof receipt of the network packet to the first computing device and/orthe second computing device before communicating the network packet. Inone embodiment, the network packet comprises a lossless protocol packet,such as a transport control protocol. In another embodiment, the payloadcomprises a lossy protocol packet, such as a user datagram protocol.

In an additional aspect, the present invention is related to a methodfor a client to prioritize network communications of the clientassociated with an application of the client. The method includesintercepting, by the client, one or more network packets associated withone or more applications of the client, and storing the one or morenetwork packets to a queue. The client determines the queued one or morenetwork packets is associated with a first application of the client.The client indicates a priority for the determined one or more networkpackets to place the determined one or more network packets ahead of atleast one network packet in the queue associated with a secondapplication of the client. The client provides the prioritized one ormore network packets for communications via a network stack of theclient.

In one embodiment, the method of the present invention includesdetermining, by the client, the queued one or more networks packets ofthe first application comprises real-time data. The real-time data mayinclude one of the following: 1) a real-time protocol, 2) a userdatagram protocol, and 3) a representation of voice or audio.

In another embodiment, the method includes preventing, by the client, atleast one network packet of the second application from beingcommunicated via the network stack ahead of the one or more networkpackets of the first application. In a further embodiment, the methodincludes holding, by the client, in the queue a network packetassociated with the second application, and releasing the held networkpacket upon communication of the one or more network packets associatedwith the first application prioritized ahead of the held network packet.

In yet another embodiment of the present invention, the method includesintercepting, by the client, the one or more network packetstransparently to the one or more applications on the client. In someembodiments, the first application is running in the foreground, and thesecond application is running in the background.

In one embodiment of the present invention, the method includesassociating a priority with the first application higher than a priorityassociated with the second application. In another embodiment, a usermay specify the priority of the first application or the secondapplication. In a further embodiment, the client receives the one ormore network packets from a computing device. Also, the one or moreapplications may provide the one or more network packets forcommunicating from the client to a computing device.

In another aspect, the present invention is related to a client forprioritizing network communications of the client associated with anapplication of the client. The client includes a mechanism forintercepting one or more network packets of the client associated withone or more applications of the client. The client also includes anetwork driver for storing the one or more networks packets to a queueand communicating the one or more network packets via a network stack ofthe client. The client further includes an agent for determining the oneor more network packets is associated with a first application of theclient, and indicating to the network driver a priority of the one ormore network packets to place the determined one or more network packetsahead of at least one network packet in the queue associated with asecond application of the client.

In one embodiment, the agent of the present invention determines the oneor more networks packets of the first application comprises real-timedata. The real-time data comprises one of the following: 1) a real-timeprotocol, 2) a user datagram protocol, and a 3) representation of voiceor audio.

In a further embodiment, the agent or the network driver of the presentinvention prevents at least one network packet of the second applicationfrom being communicated via the network stack ahead of the one or morenetwork packets of the first application. In one embodiment, the networkdriver holds in the queue a network packet associated with the secondapplication, and releases the held network packet upon communication ofthe one or more network packets associated with the first applicationprioritized ahead of the held network packet.

In another embodiment, the present invention, via the mechanism,intercepts the one or more network packets transparently to the one ormore applications on the client. In some embodiments, the firstapplication is running in the foreground, and the second application isrunning in the background. Also, the first application may have apriority higher than the second application of the client. Furthermore,the client may include a configuration mechanism for a user to specifythe priority. In some embodiments, the client receives the one or morenetwork packets from a computing device. In other embodiments, the oneor more applications provides the one or more network packets forcommunicating from the client to a computing device.

In an additional embodiment, the network driver includes a NetworkDriver Interface Specification (NDIS) driver. Also, the network drivermay operate in kernel-mode of an operating system of the client. In somecases, the agent operates in user-mode of an operating system of theclient. Furthermore, the agent or the network driver includes themechanism for intercepting one or more network packets of the client.

In yet another aspect, the present invention is related to a method forshielding from a network disruption a session established via a firstprotocol. The method includes the steps of establishing, via an agent ofa client, a session via a first protocol over a network connectionbetween the client and a device. The network connection is associatedwith a network stack. A first portion of the network stack has one ormore layers of the network stack below the layer of the first protocol,and a second portion of the network stack includes a layer for the firstprotocol and one or more layers of the network stack above the firstprotocol. The method includes detecting a disruption in the networkconnection causing the second portion of the network stack to bedisestablished, and maintaining, by the agent, the session and thesecond portion of the network stack during the disruption. The methodfurther includes re-establishing the first portion of the network stackand the network connection while maintaining the session and the secondportion of the network stack.

In one embodiment, the method includes continuing the session with themaintained second portion of the network stack and the re-establishedfirst portion of the network stack. In some embodiments, the method alsoincludes dropping, by the first and/or second portion of the networkstack, any network packets received during the disruption.

In another embodiment, the device comprises a remote access gateway oranother computing device. In some cases, the method includesestablishing the session via the first protocol of one of thefollowing: 1) secure socket layer (SSL) protocol, 2) a transport layersecurity (TLS) protocol, and 3) a tunneling protocol. Additionally, themethod of the present invention may include communicating, by the agent,real-time data via the session between the client and the device. Thereal-time data may include a real-time protocol or the real-time datamay represent voice or audio.

In some embodiments, the agent operates in user-mode of an operatingsystem of the client. In one embodiment, the first portion of thenetwork comprises one of a transport control protocol or an internetprotocol. In another embodiment, the second portion of the network stackcomprises one of 1) an internet protocol, 2) a user datagram protocol,or 3) a voice over internet protocol. Additionally, the client maycommunicate with the device via a remote display protocol. The remotedisplay protocol may be an Independent Computing Architecture (ICA)protocol or a Remote Desktop Protocol (RDP).

In another embodiment, the method of the present invention is performedtransparently to an application of the client communicating via thenetwork connection. In one embodiment, the method includes intercepting,by the agent, transparently to an application of the client one or morenetwork packets associated with the application. In one embodiment, themethod includes intercepting, by a network driver associated with thefirst portion of the stack, transparently to the application on theclient one or more network packets associated with the application.

In an additional aspect, the present invention is related to a systemfor shielding from a network disruption a session established via afirst protocol. The system has an agent of a client establishing asession between the client and a device over a network connection via afirst protocol. The system includes a network stack having a firstportion and a second portion, such as the network stack of the client.The second portion of the network stack comprises a layer for the firstprotocol and one or more layers of the network stack above the firstprotocol, and a first portion of the network stack comprises one or morelayers of the network stack below the layer of the first protocol. Thesystem includes a detector for detecting a disruption in the networkconnection causing the first portion of the network stack to bedisestablished. In operation of the system and upon detection of thedisruption by the detector, the agent maintains the session and thesecond portion of the network stack during the disruption. The clientre-establishes the first portion of the network stack and the networkconnection while the agent maintains the session and the second portionof the network stack.

In one embodiment of the system of the present invention, the agentcontinues the session with the maintained second portion of the networkstack and the re-established first portion of the network stack. In someembodiments, the first and/or second portion of the network stack dropsany network packets received during the disruption.

In one embodiment, the device of the system is a remote access gatewayor another computing device The first protocol used by the system of thepresent invention may include one of the following: 1) secure socketlayer (SSL) protocol, 2) a transport layer security (TLS) protocol, and3) a tunneling protocol. In another embodiment, the agent of the presentinvention communicates real-time data via the session between the clientand the device. The real-time data may include a real-time protocol, ora representation of voice or audio.

In some embodiments of the system, the agent operates in user-mode of anoperating system of the client. In one system embodiment, the firstportion of the network comprises a transport control protocol and/or oran internet protocol. In another embodiment, the second portion of thenetwork stack includes one of 1) an internet protocol, 2) a userdatagram protocol, or 3) a voice over internet protocol. Additionally,the client may communicate with the device via a remote displayprotocol, which may be an Independent Computing Architecture (ICA)protocol or a Remote Desktop Protocol (RDP).

In another embodiment, the system of the present invention maintains thesecond portion of the network stack and re-establishes the first portionof the network stack transparently to an application of the clientcommunicating via the network connection. In one embodiment, the agentintercepts network packets transparently to an application of the clientone or more network packets associated with the application. In oneembodiment, the system also includes intercepting, by a network driverassociated with the second portion of the stack, transparently to theapplication on the client one or more network packets associated withthe application.

The details of various embodiments of the invention are set forth in theaccompanying drawings and the description below.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, aspects, features, and advantages ofthe invention will become more apparent and may be better understood byreferring to the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1A is a block diagram depicting an embodiment for practicing theoperations of the present invention via a gateway in a networkenvironment;

FIG. 1B is a block diagram depicting another embodiment for practicingthe operations of the present invention in a peer-to-peer networkenvironment;

FIG. 1C is a block diagram depicting an embodiment of a remote accessclient of the present invention for network communications;

FIGS. 1D and 1E are block diagrams depicting embodiments of a computingdevice useful in practicing an embodiment of the present invention;

FIG. 2A is a block diagram depicting an embodiment of a peer-to-peernetwork environment for practicing an embodiment of the technique of thepresent invention for establishing a peer-to-peer communication route;

FIG. 2B is a flow diagram depicting an embodiment of the steps performedto optimize peer-to-peer route optimization technique of the presentinvention;

FIG. 3A is a block diagram depicting an embodiment of network stacks ofany of the computing devices of illustrative environments depicted inFIGS. 1A-1C;

FIG. 3B is a flow diagram depicting an embodiment of the steps performedto use a false acknowledgement of receipt of network packets tocommunicate via a lossless protocol packets constructed for transmissionvia a lossy protocol;

FIG. 3C is a flow diagram depicting an embodiment of the steps performedto communicate via a lossless protocol packets constructed fortransmission via a lossy protocol;

FIG. 4 is a flow diagram depicting one embodiment of steps performed foradjusting the maximum transmission unit parameter;

FIG. 5A is a block diagram depicting an environment of a client forproviding client-side application-aware prioritization techniques;

FIG. 5B is a flow diagram depicting one embodiment of the stepsperformed to provide client-side application-aware prioritization;

FIG. 6A is a block diagram depicting an environment of an apparatus forshielding a network disruption from a device; and

FIG. 6B is a flow diagram depicting one embodiment of the stepsperformed in to shield network disruption from a device.

DESCRIPTION

Certain illustrative embodiments of the present invention are describedbelow. It is, however, expressly noted that the present invention is notlimited to these embodiments, but rather the intention is that additionsand modifications to what is expressly described herein also areincluded within the scope of the invention. Moreover, it is to beunderstood that the features of the various embodiments described hereinare not mutually exclusive and can exist in various combinations andpermutations, even if such combinations or permutations are notexpressly made herein, without departing from the spirit and scope ofthe invention.

The illustrative embodiments of the present invention are generallydirected towards a remote access architecture for providing peer-to-peercommunications and remote access connectivity. In one illustrativeembodiment, the remote access architecture of the present provides amethod for establishing a direct connection between peer computingdevices via a third computing device, such as a gateway. The presentinvention also provides various techniques for optimizing thepeer-to-peer communications established with or without the gateway. Thepeer-to-peer communications may include real-time communications such asvoice over internet protocol (VoIP) signaling and media, video, andother real-time data applications such as web collaboration, screen ordesktop sharing, and instant messaging. In addition to establishing apeer-to-peer connection via gateway, the present invention also providesthe following techniques to optimize peer-to-peer communications: 1)false acknowledgement of receipt of network packets allowingcommunications via a lossless protocol packets constructed fortransmission via a lossy protocol, 2) payload shifting of networkpackets allowing communications via a lossless protocol of packetsconstructed for transmission via a lossy protocol, 3) reduction ofpacket fragmentation by adjusting the maximum transmission unit (MTU)parameter, accounting for overhead due to encryption, 4)application-aware prioritization of client-side network communications,and 5) network disruption shielding for reliable and persistent networkconnectivity and access, such as for mobile clients. These techniquesmay be practiced in peer-to-peer communications between two clients insome embodiments, or in other embodiments, in communications between aclient and a gateway or between one computing device via a gateway toanother computing device, such as via an SSL VPN gateway of anillustrative embodiment of the present invention.

In the illustrative embodiments of the present invention, thepeer-to-peer route optimization technique determines a more optimalroute to a resource a client may be trying to access via a gateway. Theclient and the resource accessed by the client, such as a server or apeer computer, may have a more direct route than via the gateway. Forexample, the client and the server may be located near each other butdistant from the gateway, and thus, are closer to each other than viathe gateway. Furthermore, using a gateway causes at least one additionalhop in the end-to-end network communications between the client and theserver. Instead of the client and server communicating via the gatewayusing their virtual private network (VPN) assigned internet protocol(IP) network addresses, the gateway and remote access architecture ofthe present invention facilitates the client and server communicating toeach other via a direct route in a peer-to-peer fashion without usingthe gateway. In some cases, however, the client and server may not havea direct path between each other as either the client and/or server maybe behind a firewall, such as a Network Address Translation (NAT)firewall. The peer-to-peer route optimization techniques and remoteaccess architecture of the present invention also provide techniques forthe client and server to communicate directly via traversal of thefirewall. As such, the peer-to-peer route optimization techniques of thepresent invention provides a shorter more optimal route between peercomputers than via the gateway.

In the illustrative embodiments of the present invention, the falseacknowledgement technique of an embodiment of the present inventionenables a packet constructed to be transmitted via a lossy protocol tobe communicated via lossless protocol. For example, a real time protocol(RTP) may be implemented over a user datagram protocol (UDP) for voiceover IP (VoIP) communications. A lossy or unreliable protocol, such asUDP, may be used for voice communications because, in some real-timevoice applications, it may be more important to get network packets to arecipient on time rather than getting the network packets in order orguaranteeing the delivery of network packets. However, by way of virtualprivate network and remote access solutions using a secure communicationand/or tunneling protocol, such as Secure Socket Layer (SSL) orTransport Layer Security (TLS), a real-time application data constructedto be transmitted via a lossy protocol, such as UDP, may be communicatedvia a lossless or reliable protocol such as a transport control protocol(TCP). The techniques of the present invention allow a lossy protocol,such as RTP over UDP, to be communicated via a lossless protocol such asTCP, while avoiding one or more of the lossless characteristics of thelossless protocol from being applied to the communication.

In the illustrative embodiment of the present invention, this techniquecommunicates a false acknowledgement of receipt of the lossless protocolnetwork packet to the corresponding network stacks to prevent thelossless protocol from executing algorithms that provide for reliabilityof the protocol. Using this technique, the lossy protocol can becommunicated over a lossless protocol, such as via TCP, SSL or via atunneling protocol of a gateway, for example, to make the communicationsecure, and have the lossy protocol network packets get to the recipienton time rather than getting to the recipient reliably. In oneembodiment, this technique can be used to securely communicate real-timedata communications such as VoIP over SSL or TLS between peers or via agateway.

The illustrative embodiments of the present invention also provideanother technique of payload shifting that enables a packet constructedto be transmitted via a lossy protocol to be communicated via losslessprotocol. A first computing device receives a first packet to betransmitted using an unreliable transport protocol, and creates a firstTCP packet including a first payload of the received first packet. Thefirst TCP packet is created with a TCP header having informationassociated with a TCP connection established between the first and asecond computing device. The first TCP packet is transmitted to thesecond computing device. A second packet to be transmitted using anunreliable transport protocol is received by the first computing, whichin turn creates a second TCP packet including the payload of thereceived second packet but with the TCP header information of the firstTCP packet. The second TCP packet is transmitted to the second computingdevice before receiving an acknowledgement of the receipt of the firstTCP packet from the second device. As such, the payload shiftingtechnique communicates multiple unreliable transport protocol payloadsunder a TCP header until an acknowledgement of receipt is received.

In the illustrative embodiments of the present invention, the maximumtransmission unit adjustment technique reduces the reported size of themaximum transmission unit (MTU) parameter of a network stack of a clientto take into consideration the effect of the network packet size due toencryption of a payload. Encryption of the payload of a network packetincreases the size of the network packet communicated to or by theclient, and may cause a network packet to be fragmented. For example, aserver may communicate to the client a network packet via an SSL gatewayto the client. Although the server sends a network packet that shouldmeet the MTU size the network stack of the client can handle, theencryption provided by the gateway increases the size of the networkpacket before it reaches the client. This may cause the network packetcommunicated from the server to the client via the gateway to befragmented as the increased packet size from encryption may be too largefor the MTU size of the client. The technique of the present inventionadjusts the client's reported MTU size to report a smaller size to takein account for the overhead of the encryption. This technique reducesnetwork fragmentation or otherwise prevents non-optimal fragmentation.

In the illustrative embodiments of the present invention, theprioritization technique provides for client-side and application-awareprioritization of network communications. That is, the remote accessclient of the present invention manages and controls networkcommunication prioritizations on the client. The prioritizations arebased on priorities of the application on the client. The remote accessclient transparently intercepts network communications associated withapplications executing on the client, detects the network communicationis associated with an application, and determines priorities for thenetwork communications based on a priority for the application. Forexample, an application on the client may be communicating real-timedata communications, such as VoIP, to a peer client or via a gateway.The remote access client may intercept a network packet, and detect, forexample, the network packet contains real-time data or is from a VoIPapplication. The remote access client may indicate a priority for thisnetwork packet such that the network packet may be communicated ahead ofnon-real-time data communications or ahead of network communicationsfrom other applications. As such, the prioritization techniques of thepresent invention may improve or increase the performance, operationalcharacteristics, and user experience on the client based on theapplications running on the client.

In the illustrative embodiments of the present invention, the networkdisruption shielding technique provides a persistent and reliableconnection of a client to a network, such as a peer-to-peercommunication session or a connection to a gateway. For example, amobile client, such as a laptop with a software based IP telephone, mayconnect to a network for VoIP communications. A temporary disruption ina network connection may occur when the mobile client roams betweendifferent access points in the same network, or when the client switchesbetween networks (e.g., from a wired network to a wireless network).This disrupts the network service to the client and may drop the VoIPtelephone call. Additionally, as the mobile client moves between accesspoints, the mobile client may obtain a different IP network address,such as from a new Dynamic Host Configuration Protocol (DHCP) lease.This can also cause network connectivity and VoIP telephonecommunication disruption. The techniques of the present inventiondetects a disruption in the network and shields a portion of the networkstack from the network disruption. The shielded portion of the networkstack is maintained while the other portion of the network stack isreestablished and reconnected to the network. Once the network isavailable, the present invention continues with the client's networkcommunications. In some embodiments, the network communications arequeued during the network disruption and transmitted once the network isavailable. In other embodiments, such as for real-time datacommunications, network packets are dropped during the disruption toprevent the queuing of network packets that may cause latency in thereal-time communication, such as VoIP telephone call.

Although the illustrative embodiments of the present invention may begenerally described in connection with an internet protocol (IP) basedprotocol, such as a transport control protocol (TCP) or user datagramprotocol (UDP), the techniques of the present invention may be used inany other types of networking environments with other networkingprotocols, such as any Internetwork Packet Exchange (IPX) protocol basednetworks using a Sequenced Packet Exchange (SPX) protocol. Also,although a lossy or unreliable protocol such as UDP and a lossless orreliable protocol such as TCP may be used for illustrating an embodimentof the present invention, any lossless/reliable and lossy/unreliableprotocol as known to those ordinarily skilled in the art may be used inpracticing the operations of the present invention described herein.Furthermore, although some of the illustrative embodiments of thepresent invention may be described below in relation to real-time datacommunications, such as VoIP, the techniques of the present inventionmay be applied for non-real-time data communications as one ordinarilyskilled in the art will also recognize and appreciate.

Additionally, at times, the illustrative embodiments of the presentinvention may be described in regards to peer-to-peer communications. Inone aspect, a peer-to-peer model comprises a type of network in whichany computer can act as both a server by providing access to itsresources to other computers, and can act as a client by accessingshared resources from other computers. Although in another aspect, apeer-to-peer model may not comprise a notion of a client and a server, aclient and a server may provide peer-to-peer communications as well asclient to client, server to server, or a client/server to a computingdevice such as a gateway. In an additional aspect, peer-to-peercommunications comprises a process whereby computers can exchangeinformation between each other directly without the assistance of athird party network or a device, such as a gateway. Althoughpeer-to-peer communications may be generally described as directcommunication between computers, there may be other network elementsbetween the computing devices to facilitate the transmission and/orcommunication, such as for example, a network hub.

Furthermore, although the illustrative embodiments of the presentinvention may be described peer-to-peer, point-to-point, client toserver, or otherwise, one ordinarily skilled in the art will recognizeand appreciate that the present invention may be practiced betweencomputing devices in any manner via any network topology, and that anyreference to peer-to-peer, client/server, or otherwise is not intendedto limit the present invention in any way.

In one aspect, the present invention is related to a remote accessarchitecture having a remote access client for communicating to anetwork via a gateway or peer-to-peer to another remote access client oranother computing device. The remote access architecture of the presentinvention provides systems and methods for securely communicatingnetwork traffic transmitted between a private network behind a gatewayto a client on an external network, such as public network. The remoteaccess architecture of the present invention enables separation of theclient from the private network by providing network address translation(NAT) functionality on the gateway. A VPN gateway that uses NetworkAddress Translation (NAT (provides masquerading of IP addresses of aclient to shield the private network from direct layer-2 access by theclient.

Referring now to FIG. 1A, the environment 180 depicts a system fordeploying the remote access architecture in an illustrative embodimentof the present invention. In brief overview, the environment 180includes multiple computing devices 102 a-102 c (herein also referred toas clients 105 a-105 c) connected to a network 104 via one or morenetwork connections 341 a-341 n. One or more of the clients 105 a-105 nmay connect to a server 102 a, a server farm 102 e, or a peer computingdevices 102 d via a gateway 350.

Each client 105 a-105 n includes a remote access client 120 a-120 c,which will be described in more details in connection with FIG. 1C, andone or more applications 338 a-338 n. Each of the clients 105 a-105 ncommunicate over the network 104 to the gateway 340 via a tunneling orgateway connections 341 a-341 n using any type and/or form of suitabletunneling or gateway protocols. In some embodiments, the gatewayconnections 341 a-341 n may be used for communicating securely, such asvia encapsulating and encryption, or otherwise may use any otherprotocols, such as any real-time, lossless, or lossy protocol. In otherembodiments, the gateway 340 provides a virtual private networkconnection between one or more of the clients 105 a-105 n and any of thecomputing devices 102 d-102 n.

The client 105 can be any type and/or form of computing device 102 thatcan run one or more applications 338 that access a network, such asnetwork 104. The application 338 can be any type and/or form ofapplication such as any type and/or form of web browser, web-basedclient, client-server application, a thin-client computing client, anActiveX control, or a Java applet, or any other type and/or form ofexecutable instructions capable of executing on client 105 orcommunicating via a network 104. The application 338 can use any type ofprotocol and it can be, for example, an HTTP client, an FTP client, anOscar client, or a Telnet client. In some embodiments, the application338 uses a remote display or presentation level protocol. In oneembodiment, the application 338 is an ICA client, developed by CitrixSystems, Inc. of Fort Lauderdale, Fla. In other embodiments, theapplication 338 includes a Remote Desktop (RDP) client, developed byMicrosoft Corporation of Redmond, Wash. In other embodiments, theapplication 338 comprises any type of software related to VoIPcommunications, such as a soft IP telephone. In further embodiments, theapplication 338 comprises any application related to real-time datacommunications, such as applications for streaming video and/or audio.

The clients 105 a-105 n may access any of the resources provided viacomputing devices 102 d-102 n which may be on the same network 104, orwhich may be on a separate network, such as a private network. In someembodiments, computing devices 102 a-102 n may be on a networkdisconnected and not routable from the network 104 of the clients 105a-105 n. In one embodiment, any of the clients 105 a-105 n maycommunicate with a peer computing device 102 d having a remote accessclient 102 n and application 338 d. For example, the application 338 dmay comprise a portion of a client/server or distributed applicationcorresponding to any of the applications 338 a-338 c on clients 105a-105 n. In some embodiments, any of the remote access clients 120 a-120n may communicate with the remote access client 120 n via the gateway340.

In another embodiment, any of the clients 105 a may communicate via thegateway 340 to a server 102 e running an application 338 e, which forexample, may be an application server providing email services such asMicrosoft Exchange manufactured by the Microsoft Corporation of Redmond,Wash., a web or Internet server, or a desktop sharing server, or acollaboration server. In some embodiments, any of the application 338 emay comprise any type of hosted service, such as GoToMeeting.comprovided by Citrix Systems, Inc. of Ft. Lauderdale, Fla., WebEx.comprovided by WebEx, Inc. of Santa Clara, Calif., or LiveMeeting.comprovided by Microsoft Corporation of Redmond, Wash.

In another embodiment, any of the clients 105 a may communicate via thegateway 340 to a server farm 102 n or server network, which is a logicalgroup of one or more servers that are administered as a single entity.The server farm 102 n may be running one or more applications 338N, suchas an application 338 f providing a thin-client computing or remotedisplay presentation application. In one embodiment, the server 102 e orserver farm 102 n executes as an application 338 e-338 n, any portion ofthe Citrix Access Suite™ by Citrix Systems, Inc., such as the MetaFrameor Citrix Presentation Server™, and/or any of the Microsoft WindowsTerminal Services manufactured by the Microsoft Corporation.

Still referring to FIG. 1A, the gateway 340 may comprise any type and/orform of gateway, such as a remote access server, that may be used toconnect one or more computing devices on one network to other networks.In another aspect, the gateway 340 may be used to provide a virtualprivate network connection to give a client 105 a-105 c access to aprivate network. In a further aspect, the gateway 340 may be a hardwareor software set-up that translates between two dissimilar protocols ordisjoint or disconnected networks or systems. The gateway 340 maycomprise a specialized hardware or networking device, or may be acomputing device configured to act as a gateway. As such, the gateway340 may comprise software, hardware, or any combination of software andhardware. In one embodiment, the client 105 and the gateway 340communicate via any type and/or form of gateway or tunneling protocol341 a-341 n, such as SSL or TLS, or the Citrix Gateway Protocolmanufactured by Citrix Systems, Inc. of Ft. Lauderdale, Fla.

In some embodiments, the gateway 340 may decrypt encrypted packetsreceived from a client 105 a-105 c, and may encrypt packets communicatedto a client 105 a-105 n. The gateway 340 may be used to protect aprivate network, such as network 104. In some embodiments, the gateway340 associates a client 105 a-105 c with a private IP address or an IPaddress of the private network. In one of these embodiments, when thegateway 340 receives a packet from the client 105 a-105 c, the gateway340 transforms the IP address of the packet to the IP address associatedwith the client 105 a-105 c for the private network. In someembodiments, the gateway 340 may apply access control policies tonetwork traffic to and/or from a client 105 a-105 c. For example, accesscontrols policies may be applied to a packet received from the clientprior to routing the packet to a final destination.

In one embodiment of the gateway 340, once a frame enters the gateway340 via an SSL tunnel, the packet and its payload are dispatched viacallbacks into a handlers executing in user mode, which providefunctionality for SSL decryption. In another embodiment, openSSL may beused. In other embodiments, a hardware accelerator is used. In a furtherembodiment, the gateway 340 comprises one or more blades for providingremote access. Once the packet is decrypted, it is injected into an HTTPnetwork stack where headers are assembled and passed on to the remoteaccess blade. In a remote access blade, a packet is classified by thetype of data contained within the packet. In one embodiment, the packetcontains an HTTP header requesting login and registration. In anotherembodiment, the packet seeks TCP/UDP/RAW/OTHER connection establishment.In still another embodiment, the packet contains connection-specificdata. In yet another embodiment, the packet contains a special featurerequest such as collaboration with other users, fetching of userdirectory and presence or requesting telephony functionality such asconferencing and web cast. The remote access module dispatches thepacket appropriately to the corresponding sub handler. For example, theclient 105 may request that a connection be set up to a specific machineon the private network behind the gateway 340. The remote access modulemay consult with the access control module and if a positive response isreturned, the remote access module may grant the request. In someembodiments, the remote access module 120 may grant the request byinjecting subsequent frames on the private network using a frameforwarding module utilizing NAT/PAT to correlate incoming frames tocorresponding SSL tunnels 341 a-341 n to a client 105 a-105 c.

The network 104 as illustrated in FIG. 1A can be any type of network.The network 104 can be a local-area network (LAN), such as a companyIntranet, a metropolitan area network (MAN), or a wide area network(WAN), such as the Internet or the World Wide Web. The topology of thenetwork 104 may be a bus, star, or ring network topology. The network104 and network topology may be of any such network or network topologycapable of supporting the operations of the present invention describedherein. The client 108 and gateway 340 can connect to one or morenetworks 104 through a variety of connections including standardtelephone lines, LAN or WAN links (e.g., T1, T3, 56 kb, X.25, SNA,DECNET), broadband connections (ISDN, Frame Relay, ATM, GigabitEthernet, Ethernet-over-SONET), and wireless connections or anycombination thereof. Connections can be established using a variety ofcommunication protocols (e.g., TCP/IP, IPX, SPX, NetBIOS, Ethernet,ARCNET, Fiber Distributed Data Interface (FDDI), RS232, IEEE 802.11,IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, and direct asynchronousconnections).

In one embodiment of the present invention, the gateway 340 illustratedin FIG. 1A is used to facilitate a direct peer-to-peer connectionbetween computing devices 102 a-102 n. For example, client 105 a mayestablish a tunneling session with the gateway 340 to access the peercomputing device 102 d. The gateway 340 negotiates with the remoteaccess client 120 a of client 105 a and the remote access client 120 nof computing device 102 d to enable the client 105 a to directly connectto the computing device 102 d without traversing the gateway 340. Oncethe network connection between the client 105 a and computing device 102d is established, the client 105 a can communicate in a peer-to-peermanner with computing device 102 d. The gateway 340 of the presentinvention can facilitate a direct peer-to-peer connection between any ofthe computing devices 102 a-102 n illustrated in the environment 180. Inone embodiment, the gateway 340 can facilitate a peer-to-peer connectionbetween any of the clients 105 a-105 n, for example between client 105 aand client 105 b or between client 105 b and client 105 c. In anotherembodiment, the gateway 340 facilitates a peer-to-peer connectionbetween computing devices 102 d-120 n, for example, between computingdevice 102 d and server 102 e or server farm 102 n. In otherembodiments, the gateway 340 facilitates a peer-to-peer connectionbetween one of the clients 105 a-105 n and one of the computing devices102 d-102 n. The techniques of facilitating a peer-to-peer connectionvia the gateway 340 will be discussed in more detail below inconjunction with FIGS. 2A and 2B

Referring now to FIG. 1B, the remote access client 120 of the presentinvention may be used in an illustrative embodiment of a peer-to-peerconnection without a gateway 304. For example, the gateway 340 mayfacilitate a peer-to-peer connection between any of the computing device102 a-102 n illustrated in FIG. 1, and thereafter the computing devices102 a-102 n communicate directly to each other in a peer-to-peer manner.In other embodiments, any computing device 102 a may communicatedirectly to another computing device 102 b or 102 c via a network 104without a gateway 340 facilitating the connection.

In brief overview of FIG. 1B, the remote access client 120 a may bedeployed on a client 102 a running one or more application 338 a. Thecomputing device 102 a may connect over the network 104 to computingdevice 102 b and/or computing device 102 c. Computing device 102 b maybe a peer or client computing device also comprising a remote accessclient 120 b. In some embodiments, remote access client 120 a and 120 bmay communicate with each other via network 104, and may work inconjunction with each other for application 338 a to communicate toapplication 338 b, such as for a web-based or client/server application.In other embodiments, the remote access client 120 a may communicatewith computing device 120 c which may be a server that does not executea remote access client 120.

FIG. 1C depicts a block diagram illustrating a system having a remoteaccess client 120 for routing network packets from a client 105 to anetwork 104. In brief overview, the system includes a computing device102 (herein also referred to as a client 105) having an operating systemthat includes a user mode 332, also referred to as an application oruser space, and a kernel-mode 334, which may be also referred to as thekernel or system level space. The client 105 runs an agent 326 that inone embodiment, may run in user-mode 332. The client 105 also runs afilter 322, which may, in one embodiment, execute in kernel-mode or thekernel space 334. In one embodiment, the filter 322 and the agent 326form the remote access client 120 for routing packets via a network, orfor otherwise providing remote access connectivity in accordance withthe operations of the present invention described herein. The remoteaccess client 120, or any portion thereof, such as the agent 326 or thefilter 322, may execute in user-mode 332 or kernel-mode 334.

The client 105 may also have a network stack 310, which may comprise oneor more network layers, such as any networks layers of the Open SystemsInterconnection (OSI) communications model as those skilled in the artwill recognize and appreciate. The network stack 310 may comprise one ormore protocols, such as the TCP/IP protocol over Ethernet or a wirelessprotocol, such as IEEE 802.11, as those skilled in the art willrecognize and appreciate. Furthermore, the network stack 310 may includeone or more network drivers supporting the one or more layers, such as aTCP driver or a network layer driver. The network drivers may beincluded as part of the operating system of the computing device 102 oras part of any network interface cards or other network accesscomponents of the computing device 102. Additionally, any of the networkdrivers of the network stack 310 may be customized, modified or adaptedto provide a custom or modified portion of the network stack 310 insupport of any of the techniques of the present invention describedherein. Additionally, some portions of the network stack 310 may operatein kernel-mode 334 while other portions run in user-mode 332, such as anapplication layer of the network stack 310.

The filter 322 may include a packet capturing mechanism 365, and thefilter 322 and/or packet capturing mechanism 365 may comprise a networkdriver, such as a network driver operating at any layer, or portionthereof, of a network stack 310 of the client 105. The filter 322 and/orthe packet capture mechanism 365 may comprise a driver complying withthe Network Driver Interface Specification (NDIS), or a NDIS driver. Inanother embodiment, the filter 322 and/or the packet capture mechanism365 may comprise a min-filter or a mini-port driver. The packet capturemechanism 365 may also in some embodiments operate in kernel mode 334.Although the packet capture mechanism 365 is illustrated as part of thefilter 322, the packet capture mechanism 365 may be separate from thefilter 322. Additionally, the filter 322 and the packet capturemechanism 365 may operate at different layers, or portions thereof, of anetwork stack of the client 105.

The filter 322 may use a filter table for filtering packets. Thefiltering table is used to determine what action to take againstpackets, such as packets intercepted by the packet capture mechanism365. The filter 322 can inspect the contents of the packets, such asrouting information, to determine the action to take based on thefiltering table. In some embodiments, the filter 322 may drop or acceptthe network packets depending on their content. In other embodiments,the filter 322 may route the network packets to the agent 326 based onthe packets content and/or the filtering table. The filter table mayalso be used to ensure that unwanted packets are discarded. The filter322 may be used to deny access to particular protocols or to preventunauthorized access from remote computers by discarding packets tospecified destination addresses.

In some embodiments, the filtering table includes information about aprivate network. In other embodiments, a filter 322 on a clientcomputing device 102 receives the filtering table. In one of theseembodiments, the filter 322 receives the filtering table from anapplication 338 or an agent 326 on the computing device 102. In anotherof these embodiments, the filter 322 receives configuration settingsfrom the agent 326 and stores the configuration settings in a filteringtable.

The packet capture mechanism 365 may intercept any of the networktraffic of the client 105, such as network packets associated with theapplication 338. In some embodiments, the packet capture mechanism 365intercepts network traffic transparently to the application 338, theagent 326, the gateway 340, or to any portion of the network stack 310of the client 105, such as any other driver or layer operating at alayer above or below the layer the packet capture mechanism 365operates. In this manner, the present invention can be used with andsupport any of the techniques described herein and for any applicationand any protocol used by the application. In one embodiment, the packetcapture mechanism 365 intercepts outbound packet traffic, such as anynetwork traffic communicated via network 104 and/or gateway 340. Thepacket capture mechanism 365 may forward the packets to the agent 325 ora frame monitor mechanism 360 of the agent 326. In some embodiments, thefilter 322 communicates with the agent 326 via asynchronous I/O controlmessages. In one of these embodiments, the packet capture mechanism 365may forward packets addressed to private network behind a gateway 340via asynchronous I/O control messages. In other embodiments, the filter322 communicates with the agent 326 running in the user space 334 viaUDP packets. In one embodiment, the filter 322 receives configurationsettings from the agent 326 driver via asynchronous I/O controlmessages. The configuration settings may include information regardingwhich networks, protocols, or types of packets to filter. In oneembodiment, the filter 322 stores the configuration settings in afiltering table. In another embodiment, the filter 322 receives afiltering table including the configuration settings.

In one embodiment, the filter 322 intercepts all outbound packets of theclient 105 for inspection. For example, in some embodiments, the filterintercepts a packet generated by an application 338 executing inuser-mode 332 for transmission by the client 105. If the packetsatisfies a condition listed in the filtering table, the filter 322 maytransmit the packet to the agent 326 and not to the original destinationof the packet. The filter 322 may use an asynchronous I/O controlmessage to forward the packet to the agent 326. The filter 322 maytransmit the packet to the agent 326 in accordance with or responsive toa routing table.

In some embodiments, the agent 326 and the filter 322 communicate via anIOCTL application programming interface (API), such as any IOCTLlibraries and function calls provided by the Microsoft Windows family ofoperating systems. In other embodiments, the IOCTL based interfacebetween the agent 326 and the filter 322 may be provided by any portionof the operating system running on the client 105. Although discussed interms of I/O control message and the IOCTL interface, the agent 326 andthe filter 322 may communicate via any suitable mechanism and/or means.

The kernel 334 of client 105 may include an NDIS interface. In someembodiments, the NDIS interface includes a plurality of intermediatefilters. In one embodiment, a packet passes through the NDIS interfaceand may be inspected by the plurality of intermediate filters. Althoughthe filter 322 may be provided as an NDIS driver, the filter 322 mayalso be a process or other set or type of executable instructionsexecuting in the kernel 334.

The agent 326 of the present invention may execute in the applicationspace 332 or user-mode on the client 105. In other embodiments, theagent 326 operates in kernel-mode 334. In some embodiments, the agent326 provides functionality for receiving packets from the filter 322. Inother embodiments, the agent 326 provides functionality for applying apolicy to a received packet. In still other embodiments, the agent 326provides functionality for managing an SSL tunnel to the gateway 340. Inyet other embodiments, the agent 326 provides functionality forencrypting and transmitting a packet to the gateway 340. The agent 326may include frame monitor mechanism 360. The frame monitor 360 mayinclude policies and logic for applying a policy to a received packet.The agent 326 may transmit a packet to a gateway 340 responsive to apolicy-based determination made by the frame monitor 360.

In some embodiments, the frame monitor 360 may apply a policy todetermine a condition of the client 105, or endpoint, at the time oftransmission of the packet. In other embodiments, the frame monitor 360may identify an application 338 that generated the packet. In some ofthese embodiments, the frame monitor 360 may make a policy-baseddetermination to transmit the packet to the gateway 340 responsive tothe identified application 338. In another embodiment, the frame monitor360 may perform a checksum on the packet to verify that the identifiedapplication actually generated the packet.

In other embodiments, the packet capture mechanism 365 may be includedin the agent 326 instead of or in addition to the filter 322. As such,the agent 326 may intercept network traffic. The packet capturemechanism 365 may use any hooking application programming interface(API) to intercept, hook, or otherwise obtain inbound and/or outboundpackets of the client 105, such as the network traffic associated withapplication 338.

In one embodiment, a TCP connection is initiated by an application 338executing on the client 105 for transmission of IP packets to a targetcomputing device, such as computing device 102 c of FIG. 1B or thegateway 340 in FIG. 1A. The remote access client 120 may intercept orcapture the IP packets generated by the application 338. The remoteaccess client 120 may send a TCP acknowledgement packet to theapplication 338 and terminate the TCP connection initiated by theapplication 338. Then, the remote access client 120 creates a second TCPconnection to the second computing device 102 c or the gateway 340 andtransmits the captured IP packets via the second TCP connection. In someembodiments, the remote access client 120 may store a captured IP packetin a buffer. In these embodiments, the remote access client 120 maytransmit the buffered IP packets via the second TCP connection to thesecond computing device 102 c. Storing the captured IP packets in abuffer enables preservation of the packets in the event of a disruptionin the network connection.

In one embodiment, upon receipt of the captured IP packets, the gateway340 may create a third TCP connection between the gateway 340 and thetargeted computing device 102 d, such as in FIG. 1A. The gateway 340 maymaintain a port-mapped Network Address Translation (NAT) table, enablingthe gateway 340 to transmit response packets from the target computingdevice 102 d to the port monitored by the application 338 thatoriginally generated the IP packet on the client 105. Because the client105 communicates only with a public network address of the gateway 3400,the client 105 is unaware of the network address of the target computingdevice 102 d, increasing security to the network on which the targetcomputing device 102 d resides. Similarly, since the gateway 340originates the TCP connection to the target computing device 102 d, thetarget computing device 102 d does not receive the address informationof the client 105, protecting the client 105 and the network on which itresides. Additionally, since the gateway 340 receives the IP packets,the gateway 340 may make a determination responsive to a policy orsecurity check as to whether or not to transmit the IP packets to thetarget computing device 102 d, further increasing protection to thenetwork on which the target computing device 102 d resides.

In one embodiment, the present invention provides a method for securinga packet transmitted from a private, secured network behind a gateway340 to a client 105 on an external network 104. The invention enablesseparation of the client 105 from the private network by providingnetwork address translation (NAT) functionality on the gateway 340. AVPN gateway that uses NAT provides masquerading of IP addresses of aclient 105 to shield the private network from direct layer-2 access bythe client 105. In one aspect, any portion of the remote access client120, such as the agent 326, frame monitor 360, the filter 322, andpacket capture mechanism 365, or any portion thereof may comprisesoftware, hardware, such as an ASIC or an FPGA, or any combination ofsoftware and/or hardware. In some embodiments, portions of the remoteaccess client 120 may be provided via one or more blades on the client105.

Although the remote access client 120 is illustrated with multiplecomponents, such as an agent 326 and a filter 322, one ordinarilyskilled in the art will recognize and appreciate that the operations andfunctionality of the remote access client 120 described herein may bepracticed in a single mechanism or single component. For example, insome embodiments, the operations and functionality of the remote accessclient 120 may be included within an application 338. In one embodimentfor example, the functionality and operations of the remote accessclient 120 may be provided just as an agent 326, and in anotherembodiment, just as a network driver, such as the filter 322.

In some embodiments, the remote access client 120, or any portionthereof, such as the agent 326, frame monitor 360, the filter 322, andpacket capture mechanism 365 may comprise an application, module,service, computer program, software component, web service, webcomponent, library, function, process, task, thread, or any other typeand/or form of executable instruction which is designed to and capableof executing the functionality of the present invention as describedherein, and which may operate in any portion or combination of user-mode332 and/or kernel-mode 334.

As illustrated in FIGS. 1A-1C, the remote access client 120 of thepresent invention may be deployed and used in a variety of ways tocommunicate and provided remote access over a network to other computingdevices, such as via a gateway 340 or directly between peer computingdevices. In these variety of environments, the remote access client 120may be used to practice one or more of the optimization techniques ofthe present invention as described in more detail below. For example,the remote access client 120 may be used for optimizing any real-timedata communications, such as VoIP, desktop sharing, or web conferencingin any of the illustrative environments of FIGS. 1A-1C.

In the illustrative embodiments of FIGS. 1A-1C, the computing devices102 a-120 n, such as for any of the clients 105, server, or the gateway340, may be provided as any type and/or form of computing device such asa personal computer or computer server of the sort manufactured by theHewlett-Packard Corporation of Palo Alto, Calif. or the Dell Corporationof Round Rock, Tex. FIGS. 1D and 1E depict block diagrams of a computingdevice 102 useful for practicing an embodiment of the present invention.As shown in FIGS. 1D and 1E, each computing device 102 includes acentral processing unit 102, and a main memory unit 104. As shown inFIG. 1D, a typical computing device 102 may include a visual displaydevice 124, a keyboard 126 and/or a pointing device 127, such as amouse. Each computing device 102 may also include additional optionalelements, such as one or more input/output devices 130 a-130 b(generally referred to using reference numeral 130), and a cache memory140 in communication with the central processing unit 102.

The central processing unit 102 is any logic circuitry that responds toand processes instructions fetched from the main memory unit 104. Inmany embodiments, the central processing unit is provided by amicroprocessor unit, such as: the 8088, the 80286, the 80386, the 80486,the Pentium, Pentium Pro, the Pentium II, the Celeron, or the Xeonprocessor, all of which are manufactured by Intel Corporation ofMountain View, Calif.; the 68000, the 68010, the 68020, the 68030, the68040, the PowerPC 601, the PowerPC604, the PowerPC604e, the MPC603e,the MPC603ei, the MPC603ev, the MPC603r, the MPC603p, the MPC740, theMPC745, the MPC750, the MPC755, the MPC7400, the MPC7410, the MPC7441,the MPC7445, the MPC7447, the MPC7450, the MPC7451, the MPC7455, or theMPC7457 processor, all of which are manufactured by Motorola Corporationof Schaumburg, Ill.; the Crusoe TM5800, the Crusoe TM5600, the CrusoeTM5500, the Crusoe TM5400, the Efficeon TM8600, the Efficeon TM8300, orthe Efficeon TM8620 processor, manufactured by Transmeta Corporation ofSanta Clara, Calif.; the RS/6000 processor, the RS64, the RS 64 II, theP2SC, the POWER3, the RS64 III, the POWER3-II, the RS 64 IV, the POWER4,the POWER4+, the POWER5, or the POWER6 processor, all of which aremanufactured by International Business Machines of White Plains, N.Y.;or the AMD Opteron, the AMD Athlon 64 FX, the AMD Athlon, or the AMDDuron processor, manufactured by Advanced Micro Devices of Sunnyvale,Calif. The computing device 102 may be based on any of the abovedescribed processors, or any other processor capable of operating asdescribed herein.

Main memory unit 104 may be one or more memory chips capable of storingdata and allowing any storage location to be directly accessed by themicroprocessor 100, such as Static random access memory (SRAM), BurstSRAM or SynchBurst SRAM (BSRAM), Dynamic random access memory (DRAM),Fast Page Mode DRAM (FPM DRAM), Enhanced DRAM (EDRAM), Extended DataOutput RAM (EDO RAM), Extended Data Output DRAM (EDO DRAM), BurstExtended Data Output DRAM (BEDO DRAM), Enhanced DRAM (EDRAM),synchronous DRAM (SDRAM), JEDEC SRAM, PC100 SDRAM, Double Data RateSDRAM (DDR SDRAM), Enhanced SDRAM (ESDRAM), SyncLink DRAM (SLDRAM),Direct Rambus DRAM (DRDRAM), or Ferroelectric RAM (FRAM). The mainmemory 104 may be based on any of the above described memory chips, orany other available memory chips capable of operating as describedherein. In the embodiment shown in FIG. 1E, the processor 100communicates with main memory 104 via a system bus 150 (described inmore detail below). FIG. 1E depicts an embodiment of a computing device102 in which the processor communicates directly with main memory 104via a memory port 103. For example, in FIG. 1E the main memory 104 maybe DRDRAM.

FIGS. 1D and 1E depict embodiments in which the main processor 100communicates directly with cache memory 140 via a secondary bus,sometimes referred to as a backside bus. In other embodiments, the mainprocessor 100 communicates with cache memory 140 using the system bus150. Cache memory 140 typically has a faster response time than mainmemory 104 and is typically provided by SRAM, BSRAM, or EDRAM.

In the embodiment shown in FIG. 1D, the processor 100 communicates withvarious I/O devices 130 via a local system bus 150. Various busses maybe used to connect the central processing unit 102 to any of the I/Odevices 130, including a VESA VL bus, an ISA bus, an EISA bus, aMicroChannel Architecture (MCA) bus, a PCI bus, a PCI-X bus, aPCI-Express bus, or a NuBus. For embodiments in which the I/O device isa video display 124, the processor 100 may use an Advanced Graphics Port(AGP) to communicate with the display 124. FIG. 1E depicts an embodimentof a computer 102 in which the main processor 100 communicates directlywith I/O device 130 b via HyperTransport, Rapid I/O, or InfiniBand. FIG.1E also depicts an embodiment in which local busses and directcommunication are mixed: the processor 100 communicates with I/O device130 a using a local interconnect bus while communicating with I/O device130 b directly.

The computing device 102 may support any suitable installation device116, such as a floppy disk drive for receiving floppy disks such as3.5-inch, 5.25-inch disks or ZIP disks, a CD-ROM drive, a CD-R/RW drive,a DVD-ROM drive, tape drives of various formats, USB device, hard-driveor any other device suitable for installing software and programs suchas the remote access client software 120 related to the presentinvention.

The computing device 102 may further comprise a storage device 128, suchas one or more hard disk drives or redundant arrays of independentdisks, for storing an operating system and other related software, andfor storing application software programs such as any program related tothe remote access client 120 of the present invention. Optionally, anyof the installation devices 118 could also be used as the storage device128. Additionally, the operating system and the proxy software 120 canbe run from a bootable medium, for example, a bootable CD, such asKNOPPIX®, a bootable CD for GNU/Linux that is available as a GNU/Linuxdistribution from knoppix.net.

Furthermore, the computing device 102 may include a network interface118 to interface to a Local Area Network (LAN), Wide Area Network (WAN)or the Internet through a variety of connections including, but notlimited to, standard telephone lines, LAN or WAN links (e.g., 802.11,T1, T3, 56 kb, X.25), broadband connections (e.g., ISDN, Frame Relay,ATM), wireless connections, or some combination of any or all of theabove. The network interface 118 may comprise a built-in networkadapter, network interface card, PCMCIA network card, card bus networkadapter, wireless network adapter, USB network adapter, modem or anyother device suitable for interfacing the computing device 102 to anytype of network capable of communication and performing the operationsdescribed herein.

A wide variety of I/O devices 130 a-130 n may be present in thecomputing device 102. Input devices include keyboards, mice, trackpads,trackballs, microphones, and drawing tablets. Output devices includevideo displays, speakers, inkjet printers, laser printers, anddye-sublimation printers. The I/O devices may be controlled by an I/Ocontroller 123 as shown in FIG. 1D. The I/O controller may control oneor more I/O devices such as a keyboard 126 and a pointing device 127,e.g., a mouse or optical pen. Furthermore, an I/O device may alsoprovide storage 128 and/or an installation medium 118 for the computingdevice 102. In still other embodiments, the computing device 102 mayprovide USB connections to receive handheld USB storage devices such asthe USB Flash Drive line of devices manufactured by Twintech Industry,Inc. of Los Alamitos, Calif.

In further embodiments, an I/O device 130 may be a bridge 170 betweenthe system bus 150 and an external communication bus, such as a USB bus,an Apple Desktop Bus, an RS-232 serial connection, a SCSI bus, aFireWire bus, a FireWire 800 bus, an Ethernet bus, an AppleTalk bus, aGigabit Ethernet bus, an Asynchronous Transfer Mode bus, a HIPPI bus, aSuper HIPPI bus, a SerialPlus bus, a SCI/LAMP bus, a FibreChannel bus,or a Serial Attached small computer system interface bus.

A computing device 102 of the sort depicted in FIGS. 1D and 1E typicallyoperate under the control of operating systems, which control schedulingof tasks and access to system resources. The computing device 102 can berunning any operating system such as any of the versions of theMicrosoft® Windows operating systems, the different releases of the Unixand Linux operating systems, any version of the MacOS® for Macintoshcomputers, any embedded operating system, any real-time operatingsystem, any open source operating system, any proprietary operatingsystem, any operating systems for mobile computing devices, or any otheroperating system capable of running on the computing device andperforming the operations described herein. Typical operating systemsinclude: WINDOWS 3.x, WINDOWS 95, WINDOWS 98, WINDOWS 2000, WINDOWS NT3.51, WINDOWS NT 4.0, WINDOWS CE, and WINDOWS XP, all of which aremanufactured by Microsoft Corporation of Redmond, Wash.; MacOS,manufactured by Apple Computer of Cupertino, Calif.; OS/2, manufacturedby International Business Machines of Armonk, N.Y.; and Linux, afreely-available operating system distributed by Caldera Corp. of. SaltLake City, Utah, Java or Unix, among others.

In other embodiments, the computing device 102 may have differentprocessors, operating systems, and input devices consistent with thedevice. For example, in one embodiment the computer 102 is a Zire 71personal digital assistant manufactured by Palm, Inc. In thisembodiment, the Zire 71 operated under the control of the PalmOSoperating system and includes a stylus input device as well as afive-way navigator device.

Moreover, the computing device 102 can be any workstation, desktopcomputer, laptop or notebook computer, server, handheld computer, mobiletelephone, any other computer, or other form of computing ortelecommunications device that is capable of communication and that hassufficient processor power and memory capacity to perform the operationsdescribed herein.

In one aspect, the present invention is related to providing varioustechniques for optimizing communications between computing devices, suchas depicted in any of the illustrative environments FIGS. 1A-1C. Thepresent invention provides the following techniques, which may bepracticed stand-alone or in any combination: 1) peer-to-peer routeoptimization, 2) communications via a lossless protocol of packetsconstructed for transmission via a lossy protocol, 3) reducing networkfragmentation by adjusting maximum transmission unit (MTU) adjustment toaccount for encryption, 4) client-side application-aware networkcommunication prioritization, and 5) shielding a device from networkdisruption. The peer-to-peer route optimization technique will bediscussed in conjunction with FIGS. 2A and 2B, techniques forcommunications via a lossless protocol of packets constructed fortransmission via a lossy protocol are discussed in conjunction withFIGS. 3A and 3B, the MTU adjustment technique in conjunction with FIG.4, the client-side application-aware prioritization technique inconjunction with FIGS. 5A and 5B, and the network disruption shieldingin conjunction with FIGS. 6A and 6B.

In one aspect, the present invention is related to providing apeer-to-peer route optimization technique between a first computingdevice accessing a second computing device via a gateway, such as thegateway 340 illustrated in FIG. 1A. The peer-to-peer routing techniquesprovides a more optimal and direct communication between computingdevices establishing or attempting to establish a communication sessionvia a gateway. The illustrative method 260 of an embodiment of thepresent invention will be discussed in view of the illustrativeenvironment 200 of FIG. 2A. In brief overview, the environment 200includes a gateway 340 providing remote access connectivity to a privatenetwork, such as a network with IP address ranges 10.10.10.XXX. Thegateway 340 in association with the private network may have assigned anIP address of 10.10.10.2 for communications on the private network. Thisprivate network may include a server 102 c. Also, the private networkcomprises a telecommunication device 210 c, such as any type and/or formof VoIP telephone. The telecommunication device 210 c is assigned IPaddress 10.10.10.100 on the private network.

In one embodiment, the server 102 comprises a signaling server, whichmay provide any type and/or form of signaling services for establishinga communication session between computing devices, such as a firstcomputing device 102 a and a second computing device 102 b. In oneembodiment, the server 102 c supports a Session Initiation Protocol,SIP, which is an Internet Engineering Task Force (IETF) standardprotocol for initiating an interactive user session that involvesmultimedia elements such as video, voice, chat, gaming, and virtualreality. In one embodiment, SIP works in the application layer of theOpen Systems Interconnection (OSI) communications model. In someembodiments, the first computing device 102 a initiates a session viasignaling, such as via the SIP protocol, to the signaling server 102 cvia signaling path 220. In one embodiment, the signaling server 102 c inconjunction with the gateway 340 is used for establishing a media path225 between the first computing device 102 a and the second computingdevice 102 b, such as for a VoIP telecommunication session betweentelephones 210 a and 210 b.

The first computing device 102 a of environment 200 may be part of anetwork, private or public, accessing the gateway 340 via network 104over the connection 341 a and traversing the firewall 205 a. Thefirewall 205 a provides access to and traversal of a public network, andhas assigned the IP address of 24.24.24.100. The first computing device102 a may be in communication with, or interfaced or coupled to atelecommunication device 210 a, such as a VoIP communication device, orany other real-time data communication device. The second computingdevice 102 b may be part of a private network and have assigned the IPaddress of 192.168.20.20. Additionally, the second computing device 102b may include a software based telecommunication device 210 b, such assoftware-based VoIP telecommunication device or program. The secondcomputing device 102 b may access the gateway 340 via network 104 overconnection 341 b and traversing firewall 205 b having a public networkIP address of 216.216.10.10. The firewalls 205 a and 205 b may be anytype and/or form of firewall as known to those ordinarily skilled in theart, such as a NAT firewall.

The first computing device 102 a and second computing device 102 b ofFIG. 2A includes and uses the remote access client 120 of the presentinvention to provide an ad-hoc peer-to-peer virtual network connectivityin the environment 200. In addition to maintaining a tunnel and virtualprivate connection, such as an SSL VPN connection, to the gateway 340,the remote access client 120 of the present invention also has logic,functionality, and operations to establish a direct ad-hoc connection,such as an SSL VPN connection, to a peer it is trying to reach. In viewof FIG. 2A, the illustrative method 260 of FIG. 2B will be used todiscuss how a peer-to-peer secure communication session is establishedfor the media path 225 in one illustrative embodiment of the presentinvention. The peer-to-peer routing technique of the present inventionas illustrated by method 260 provides better voice quality and reduceslatency related to VoIP communications as well as other real-time datacommunications.

In brief overview of illustrative method 260, at step 262, the computingdevices 102 a and 102 b establish tunneling sessions with the gateway340. At step 264, the first computing device 102 a initiates a sessionto second computing device 102 b via gateway 340 using signalingprotocol via the signaling path 220 to signaling server 102 b. Thesession may be initiated by the telecommunication device 102 a incommunication with the first computing device 102 a. At step 266, asignaling server 102 c sets up the telecommunication session, and atstep 268, provides the first computing device 102 a with a first networkidentifier of the second computing device 102 b. The first networkidentifier comprises the network address, such as a host name or IPaddress, of the second computing device 102 b based on its IP addressestablished via the tunnel 341 b with the gateway 340. At step 270, thefirst computing device 102 a communicates to the second computing device102 b using the first network identifier to establish a connection orcommunication session.

In further overview, at step 272, the gateway 340 intercepts thecommunications by the first computing device 102 a and provides thefirst computing device 102 a a second network identifier for the secondcomputing device 102 b. The second network identifier comprises an IPaddress or host name of the second computing device 102 a directly orpublicly accessible by the first computing device 102 a, such as thelast known public IP address of the second computing device 102 b. Atstep 274, in one embodiment, the gateway 340 communicates to the secondcomputing device 102 b to request the second computing device 102 bestablish a swimmer session for first computing device 102 a to connectto the second computing device 102 b via firewall 205 b. In someembodiments, the gateway 340, at step 276, may negotiate or otherwiseprovide encryptions keys for the first computing device 102 a and secondcomputing device 102 b. At step 278, the first computing device 102 aestablishes a direct connection, communication session, or media path225 to the second computing device 102 b. In other embodiments, at step280, the first computing device 102 a and/or second computing device 102b match encryption keys received by the other computing device beforeallowing communications.

In some embodiments of illustrative step 262, the computing device 102 aand 102 b may establish a connection with the gateway 340 by anysuitable means and/or mechanisms, such as by any type and/or form oftunneling or gateway protocol. In some embodiments, the connections 341a and 341 b to the gateway 340 may form a virtual private networkconnection, and in other embodiments, may use SSL or TLS to providesecure communications to the private network, such as the privatenetwork identified by the IP range 10.10.10.XXX in illustrative FIG. 2A.In one embodiment, the computing devices 102 a and 102 b connect to thegateway 340 by traversing a firewall 205 a-205 b via a public network,while, in other embodiments, the computing devices 102 a and 102 b mayconnect to the gateway 340 via a private network, and may not traverse afirewall 205 a-205 b. One ordinarily skilled in the art will recognizeand appreciate the variety of ways the computing devices 102 a-102 b mayconnect to and communicate with the gateway 340.

At illustrative step 264, in one embodiment, the telecommunicationdevice 210 a, such as a hard IP phone, initiates a telecommunicationsession, such as a telephone call, to the telecommunication device 210b, such as a soft IP phone. In some embodiments, the telecommunicationdevice 210 a initiates the telephone call by indicating the extension ofthe telecommunication device 210 b. When the telecommunication device210 a initiates the telecommunication session, this initiation,indication, or request to establish a telecommunication session or mediasession may be sent to the signaling server 102 a via SIP protocol, aproprietary signaling protocol, or any other type of protocol suitablefor signaling. The signals are communicated via signaling path 220 viathe tunneling session 341 a to the gateway 230 and reach the signalingserver 102 c via the intranet routes of the private network behind thegateway 340.

Although the illustrative embodiment of method 260 is discussed in viewof VoIP or telecommunication signaling and sessions, one ordinarilyskilled in the art will recognize and appreciate that the presentinvention may be used for initiating any type and/or form ofcommunication session, real-time or otherwise, such as an interactiveuser session that involves multimedia elements such as video, voice,chat, gaming, and virtual reality. As such, the telecommunicationdevices 210 a-210 b, signaling/signal path 220, and signaling server 120a may accordingly and suitably comprise the type and/or form of device,signaling, protocols, and communications corresponding to the typeand/or form of communication session.

In some embodiments of illustrative step 266, the signal server 102 cmay set up, negotiate, or establish any type and/or form ofcommunication session, and in one embodiment the signaling server 102 csets up a telecommunication session, such as the VoIP telephone callinitiated by the telecommunication device 210 a. When setting up thetelecommunication or other media session, the signaling server 102 c, atstep 270, instructs, requests, signals or otherwise communicates to theinitiating telecommunication device 210 a and/or first computing device102 a to contact, signal, connect, or otherwise communicate to the peertelecommunication device 210 b via a certain network address. In someembodiments, the network address provided by the signaling server 102 cto the initiating telecommunication device 210 a comprises the networkaddress for the computing device 102 b on the private network, i.e.,10.10.10.XXX, behind the gateway 340. In one embodiment, the networkaddress for the peer telecommunication device 210 b may comprise anenterprise private network address.

At this point, instead of contacting the peer telecommunication device210 b via its VPN private IP address, the illustrative method of 260,via the remote access client 120 facilities the telecommunication device210 a and/or the first computing device 102 a to directly contact thepeer or target telecommunication device 210 b or the second computingdevice 102 b. The techniques of the present invention is not specific toany VoIP protocol, and may be applied to any other protocols, such asany peer-to-peer protocol between computing devices. The techniques ofthe present invention makes decisions by way of the IP address of theresource a client is trying to connect with.

At step 270, when the telecommunication device 210 a initiates a dataconnection to the telecommunication device 210 b with the first networkaddress provided by the signaling server 120 c at step 268, such as theVPN private IP address of the soft IP phone, the gateway 340 interceptsthe communication to provide the telecommunication device 210 and/orfirst computing device 102 b with a second network address forcontacting the telecommunication device 210 b. In one embodiment, thegateway 340 intervenes and sends an out of band signal over the sameestablished VPN tunnel 341 a to the first computing device 102 a that isfacilitating traffic for the hard IP phone 210 a. One ordinarily skilledin the art will recognize and appreciate that the gateway 340 maycommunicate to the telecommunication device 210 and/or computing device102 a that network address for contacting the computing device 102 band/or telecommunication device 210 b directly by any suitable meansand/or mechanisms. For example, the gateway 340 may communicate thesecond network address to the first computing device 102 a via a secondtunneling session.

In some embodiments, the gateway indicates to the first computing device102 a of the last known public IP address that the second computingdevice 102 b which is running the soft IP phone 210 b used to contactthe gateway 340. In other embodiments, this public IP may not be theactual IP address of the second computing device but may be the IPaddress of the firewall 205 b that the second computing device 102 b isbehind. If the computing device 210 a contacts the public IP address ofthe firewall 205 b directly, packets may be rejected by the firewall 205b. In these embodiments, the gateway 340 instructs the computing device102 b to establish what is known to those skilled in art as a swimmersession to the first computing device 102 a. A forward hole is punchedin the firewall 205 b via which the first computing device 102 a cantraverse or get back in. In other embodiments, any suitable means and/ormechanism may be used to allow the first computing device 102 a totraverse the firewall 205 b to connect and communicate with the secondcomputing device 102 b.

Although illustrative method 260 is discussed in conjunction withenvironment 200 of FIG. 2A having the second computing device 102 nbehind a firewall 205 a, as one ordinarily skilled in the art willrecognize and appreciate, the illustrative method 260 can be used inenvironments where the second computing device 102 b is directlyaccessible without traversing a firewall 205 a. As such, theillustrative method 260 may not need to at step 274 instruct the secondcomputing device 102 b to provide a swimmer session or other mechanismfor the first computing device 102 a to connect to the second computingdevice 102 b.

In some embodiments, the gateway 340, at step 276, may negotiate asecret key between the computing devices 102 a-103 b for securecommunications. The remote access client 120 on the computing devices102 a-102 b may use this key for secure and encrypted communicates,and/or to authenticate or authorize the other computing device. In otherembodiments, to ensure that malicious computing devices do not takeadvantage of this open hole, the gateway 340 at step 276 negotiates asecret key between the two computing devices 102 a and 102 b and therespective remote access clients 120 ensure that the keys match beforeallowing data communication. For example, in the embodiment ofestablishing a swimmer session, this key ensures that the packets comingin the open hole are from the computing device that the swimmer sessionwas meant for.

In other embodiments, the gateway 340 does not perform step 276 toprovide a secure mechanism of peer-to-peer communication sessionsbetween the computing devices 102 a-102 b. For example, the computingdevices 102 a-102 b may be in the same private enterprise network andtherefore, may be trusted. In further embodiments, instead of thegateway 340 negotiating a secret key, the computing devices 102 a-102 buse any suitable means and/or mechanism for authenticating and/orauthorizing the other computing device for peer-to-peer communications.In some embodiments, the computing devices 102 a-102 b may authenticateand/or authorize via the gateway tunneling sessions, such as via path341 a, or at step 280, via the media path 225 established at step 278.For example, the remote access clients 120 of each computing device 102a-102 b may check for matching keys over established media path 225before allowing any data to be communication over the connection 225.

At step 278, the direct media path 224 for any type and/or form ofcommunications is established between the computing devices 102 a-102 bwithout traversing the gateway 340, and, in some embodiments, not usingthe respective VPN assigned IP addresses of the computing devices 102a-102 b but instead their public IP address or the IP address assignedto them by their resident network. Using the techniques of the presentinvention, the respective remote access client 120 of computing devices102 a-102 b act as temporary peer-to-peer SSL gateways to each other,decrypting each other's SSL session directly without communicating viathe gateway 340. The direct peer-to-peer communication session via path225 avoids the extra-hop via the gateway 340. This will reduce anylatency due to taking a longer route via the gateway 340, and willimprove the quality, performance, and experience of real-time datacommunications, such as the VoIP communications illustrated in FIG. 2A.

In some embodiments, the gateway 340 may be configured to automaticallyperform the techniques of illustrative method 260 every time a computingdevice 102 is trying to establish a peer-to-peer communication sessionor otherwise access a resource via the gateway 340. In otherembodiments, the gateway 340 may be configured to automatically performthe techniques of the illustrative method 260 only for a certain IPaddress range either for a source IP address, a destination IP address,or any combinations thereof. In further embodiments, the gateway 340 mayperform this technique based on the type of application and/or resourcebeing accessed via the gateway 340. For example, in one embodiment, thegateway 340 may automatically perform this technique for any type ofdesktop or screen sharing application sharing screen data via thegateway 340. In other embodiments, the gateway 340 may determine toperform this technique based on any type and/or form of business rules,access control policies, or other configuration, algorithm, andstatistics. For example, the gateway 340 may perform this techniquebased on ping-based timing statistics between peer computing devices. Ifthe peer computing devices are closer to each other than the gateway340, the gateway performs the peer-to-peer routing technique. Oneordinarily skilled in the art will recognize and appreciate the variousways the gateway of the present invention may be adapted or otherwiseconfigured to perform the peer-to-peer routing technique of the presentinvention.

In one aspect, the present invention is related to allowingcommunications via a lossless protocol packets constructed fortransmission via a lossy protocol. In one technique illustrated in FIG.3B, the present invention use a false acknowledgement technique whencommunicating a lossy or unreliable protocol via a lossless or reliableprotocol, such as, for example, communicating RTP over UDP via a TCP orSSL/TCP connection. In another technique illustrated in FIG. 3C, thepresent invention uses payload shifting to communicate via a losslessprotocol packets constructed for transmission via a lossy protocol. Insome embodiments, these techniques of the present invention helpsachieve Transport Layer Security (TLS) at a UDP level as one ordinarilyskilled in the art will recognize and appreciate in view of thedescription below.

The illustrative method 360 of the embodiment of the present inventionfor practicing the false acknowledgement technique will be discussed inview of the illustrative environment 300 of FIG. 3A and additionally inview of FIGS. 1A-1E. In brief overview, the environment 300 comprises aclient 105 a of computing device 102 a in communications with a peerclient 105 b of computing device 102 b or alternatively, the gateway 340via network 104. In some embodiments, the client 105 a may traverse IProuters 305 a-305 b or the network 104 may have IP routers 305 a-305 b.Although, in other embodiments, the computing devices 102 a-102 b andgateway 340 may be on the same network 104. Additionally, atelecommunication device 210 a may be associated with client 105 a and asecond telecommunication device 210 b may be associated with the peerclient 105 b or the gateway 340.

Client 105 a may comprise a first network stack 310 a, and the client105 or gateway 340 may comprise a second network stack 310 b. Thenetwork stacks 3201 a-310 a may comprise one or more network layers,such as any networks layers of Open Systems Interconnection (OSI)communications model. For example, as illustrated in FIG. 3A, thenetwork stacks 310 a-310 b comprises a TCP/IP 343 a-343 communicationlayer communication on top of the frame layer that is suitable as knownto those skilled in art for a TCP/IP based network 104. The TCP layer343 a-343 b comprises an illustrative embodiments of a reliable orlossless protocol. For example, in TCP 343 a-343 b as known to thoseordinarily skilled in the art, the network stack 310 a-310 b or anydrivers or mechanisms thereof, such as a TCP driver, may performalgorithms and operations, and comprise logic or functionality toprovide one or more of the lossless or reliable characteristics of theprotocol. For example, to support TCP 343 a-343 b, the network stack 310a-320 b may perform packet ordering, packet retransmission,acknowledgements of receipt of packet, a flow control algorithm, asliding window algorithm, and/or a nagle's algorithm, and any otherreliability related operations and algorithms as one ordinarily skilledin the art will recognize and appreciate in view of TCP 343 a-343 b orany other lossless protocol.

Additionally, the networks stacks 310 a-310 b may comprise an SSL 341a-341 b layer for supporting SSL or SSL VPN communications. For example,the SSL layer 341 a-341 b may be used for a gateway or tunneling sessionbetween remote access clients 120 or between a remote access client 120and a gateway 340. As illustrated in FIG. 3A, the network stacks 310a-310 b may also provides a layer for a lossy protocol 342 a-342 b, suchas UDP, to be communicated over the lossless protocol 343 a-343 b, suchas TCP. In some embodiments, the lossy or unreliable protocol 342 a-342b may comprises Real Time Protocol (RTP) over UDP, and may comprise apayload have any type and/or form of real-time data, such anyrepresentation of voice or audio. In other embodiments, the lossyprotocol 342 a-342 b may carry the VoIP over communications to and fromthe client 105 a in an established VoIP session, such as a sessionestablished via illustrative method 260 discussed above in connectionwith FIGS. 2A and 2B. A lossless protocol, such as UDP 342 a-342 b maybe chosen for real-time applications like voice, because it may be moreimportant to get packets to the recipient, such as peer client 105 b, ontime rather than getting the packets in a reliable manner, such as via alossless protocol.

The network stacks 310 a-310 b also include a shim 322 a-322 b of theremote access client 120 of the present invention. The shim 322 a-322 bmay comprise any portion of the remote access client 120, and in someembodiments, comprises a network driver, network driver interface, orother network layer related mechanism for providing the falseacknowledgement technique of the present invention as described herein.The shim 322 a-322 b may comprise software, hardware, or any combinationof software and hardware. In one embodiment, the shim 322 a-322 b mayoperate at the IP layer of the network stack prior to a network packetreaching the TCP layer 343 a. In other embodiments, the shim 322 a-322 bmay operate at the TCP layer 343 a-343 b. One ordinarily skilled in theart will recognize and appreciate that the shim 322 a-322 b may operatein any manner associated with the layer of operations of the losslessprotocol in the network stack 310 a-310 b, including in or adjacent tothe layer of the lossless protocol.

The false acknowledgement technique of the present invention asillustrated by method 360 of FIG. 3B allows a lossy protocol, such asUDP 342 a-343 b, to be communicated via a lossless protocol, such as TCP343 a-343 b. By the shim 322 a-322 b issuing a false acknowledgement ofreceipt of a TCP packet, the technique of the present inventionsprevents or avoid the reliability mechanisms, operations and algorithmsof the lossless protocol, such as in the example of TCP 343 a-343 b, anyof the packet ordering, packet retransmission, a flow control algorithm,a sliding window algorithm, and/or a nagle's algorithm. As such, thelossy protocol 342 a-342 b can be communicated over a lossless protocol343 a-343 b but maintain its lossy or unreliable characteristics whichmay be desired such as in real-time data communications. This techniquealso enables the lossy protocol to be communicated securely, or traversea gateway via a tunneling protocol, or simply via TCP/IP while notapplying the lossless characteristics of the lossless protocol to thelossy protocol communications.

In brief overview of illustrative method 360, at step 365, the computingdevices 102 a and 102 b or the gateway 340 establish a lossless protocolbased connection, such as a TCP connection, by which lossless protocolpackets are communicated. At step 370, the remote access client 120 ofthe present invention may detect that the payload of a lossless protocolpacket comprises a lossy protocol, such as RTP or UDP, or otherwisecomprises real-time data. In one embodiment, at step 375, theillustrative method 360 may encrypt the payload with a key, such as akey provided via an out of band TLS or SSL session of step 367. At step380, a false acknowledgement of receipt of the lossless protocol packetmay be communicated or otherwise provided to the network stacks 310a-310 b, such as by the shim 322 a-322 b. In response to the receipt ofthe false acknowledgement of receipt of the lossless protocol packet, atstep 385, the respective network stacks 310 a-310 b do not execute oneor more, or all of the algorithms and operations that provide thereliable or lossless characteristics of the lossless protocol. At step390, the lossless protocol packet with the lossy protocol payload iscommunicated between the network stacks 310 a-30 b.

At step 365 of illustrative method 360, the lossless protocol connectionmay be established via any suitable means and/or mechanisms using antype and/or form of lossless protocol. In one embodiment, the networkstack 310 a of a client 105 a establishes a lossless protocolconnection, such as TCP, to a peer client 105 a having network stack 310b. In another embodiment, the network stack 310 a of client 105 aestablishes a lossless protocol connection to a gateway 340 havingnetwork stack 310 b. Additionally, the lossless protocol connection ofstep 365 may be established in a secured manner, such as SSL, or as avirtual private connection. Although the network stacks 310 a-310 b areillustrated as having the same network layers, one ordinarily skilled inthe art will recognize and appreciate that the network stacks may havecorresponding layers, which may be of different versions or associatedwith different operating systems and/or drivers, and that each networkstack 310 a-310 b may have additional layers, less layers or differentlayers.

At illustrative step 360, in one embodiment, the remote access client120 intercepts a network packet, such as via the packet capturemechanism 365, and inspects the network packet by any suitable meansand/or mechanisms to determine the type of the protocol used in thepayload of the network packet, or the type of contents in the payload ofthe network packet. In some embodiments, the shim 322 a-322 b of theremote access client 120 may be used for intercepting and inspecting thenetwork packet. In one embodiment, the remote access client 120 mayintercept a network packet and determine if the network packet comprisesany lossless protocol or a specific lossless protocol, such as TCP. Ifthe network packet is a lossless protocol, the remote access client 120checks the payload to determine the type of protocol and/or the type ofdata. In one embodiment, the remote access client 120 may determine byany suitable fields of the payload of the network packet, such as anyportion of header of the lossy protocol representing the payload, thatthe payload has a lossy protocol content. In another embodiment, theremote access client 120 may determine by any data of the payload, ifthe payload comprises a lossy protocol or comprises real-time data.

In one embodiment, the remote access client 120 determines that a TCPpacket comprises a payload of RTP or UDP, and applies an encryption ofthe payload. The remote access client 120 may encrypt the payload of thenetwork packet using any type and/or form of encryption with a keyprovided in any suitable manner. In some embodiments, the key or cipheris negotiated via an out of band TLS session between the clients 105a-105 b or the client 105 a and gateway as shown in FIG. 3A as opposedto, in other embodiments, a traditional TLS session where the session isfirst negotiated and the same socket is used for data communication. Insome embodiments, the encryption at step 375 is performed on a packet bypacket basis. In another embodiment, encryption is performed on multiplepackets at a time.

At step 380 of illustrative method 360 of the present invention, a falseacknowledgment of receipt of the network packet, e.g., the losslessprotocol packet, is issued, communicated, or otherwise provided to thenetwork stacks 310 a-310 b comprising the respective sending andreceiving computing devices 102 a-120 b, or gateway 340. The shim 322a-322 b, any portion of the remote access client 120, or any portion ofthe network stack 310 a-310 b may issue the false acknowledgment ofreceipt of the network packet. In one aspect, the false acknowledgementof receipt of the network packet is false in the sense that it iscommunicated not to acknowledge the actual receipt of a network packetbut in order to prevent the lossless and reliable mechanisms of thelossless protocol associated with the network stacks 310 a-310 b. Assuch, the false acknowledgement of receipt of the network packet maycomprise the same form and/or type as an actual acknowledgement ofreceipt of the network packet.

In some embodiments, the false acknowledgement of receipt is issued tothe network stacks 310 a-310 b prior to communicating the network packetor packets. In other embodiments, the false acknowledgement of receiptis issued after communicating the network packet(s) but at a time or ina manner such as to prevent the lossless protocol mechanisms of thereceiving network stack 310 a-310 b from being applied to thetransmitted network packet. In one embodiment, the false acknowledgmentof receipt of the network packet is issued for each network packet, andin another embodiment, may be issued once per communication session orlossless protocol connection. Furthermore, one ordinarily skilled in theart will recognize and appreciate the false acknowledgement of receiptmay be performed in different places in the network stack 310 a-310 bfor different operating systems. For example, in one embodiment, theacknowledgement of receipt may be issued at the Network Driver InterfaceSpecification (NDIS) driver level in the Microsoft Family of WindowsOperating Systems.

At step 385 of illustrative method 360, the network stack 310 a-310 breceiving the false acknowledgment of receipt of the network packet fromstep 380 may in response to such receipt, may not execute, stopexecuting, or prevent from executing any one or more algorithms andoperations providing one or more lossless characteristics of thelossless protocol. For example, in the embodiment of TCP as the losslessprotocol, the network stack 310 a-310 b may not execute any one or moreof the following with respect to the network packet, or the TCPconnection: packet ordering, packet retransmission, a flow controlalgorithm, a sliding window algorithm, and/or a nagle's algorithm. Insome embodiments, the false acknowledgment of receipt must be receivedon a packet by packet basis to prevent the lossless layer of the networkstack 310 a-310 b from employing reliability algorithms. As such, thesending network stack 310 a-310 b can determine on a packet by packetbasis which packets to apply the false acknowledgment techniques of thepresent invention to. There may be some lossless protocol networkpackets comprising the lossy protocol for which the reliabilityalgorithms of the lossless protocol should be applied. In otherembodiments, the false acknowledgment of receipt of the network packetmay be received once for the lossless protocol connection to preventemploying reliability algorithms for any subsequent packets receivedduring the lossless protocol session or connection.

At step 390, the illustrative method 360 communicates the losslessprotocol packet having the lossless protocol payload via the networkstacks 310 a-310 b. In one embodiment, the lossless protocol packet iscommunicated after step 385, or in other embodiments, before step 385.So, although the lossless protocol packet becomes lost in the network,no attempt is made to reclaim the packet as one would expect for a lossyprotocol packet.

Although the illustrative embodiment of method 360 is discussed using afalse acknowledgment of receipt of the network packet such as in TCP,any type and/or form of indication, request, or instruction may becommunicated to the network stacks 310 a-310 b to prevent employing anyreliability or lossless algorithms of the lossless protocol. In someembodiments, the lossless protocol layer of the network stack 310 a-310b may be adapted or configured to have a configuration, flag, orinstruction to not use the reliability algorithms either on a packet bypacket basis, or a session or connection basis. For example, thelossless protocol may have fields, such in a header of a losslessprotocol packet, that indicates whether reliability should be discardedor avoided for the packet.

Referring now to FIG. 3C, another embodiment of steps taken to transmitpackets constructed according to a lossy protocol via a losslessprotocol is shown by illustrative method 345, which may also be referredto as a payload shifting technique. In brief overview of illustrativemethod 345, at step 348, a first packet to be transmitted using anunreliable transport protocol is received by a first device, such asclient 105. At step 350, the first device 105 creates a first TCP packetincluding a first payload of the received first packet and a first TCPheader of information associated with a TCP connection establishedbetween the first device 105 and a second device. The first device 105transmits the first TCP packet to the second device at step 352. At step354, the first device 105 receives a second packet to be transmittedusing an unreliable transport protocol, and at step 356, creates asecond TCP packet including a second payload of the received secondpacket and the first TCP header information. At step 358, the firstdevice transmits, before receipt of an acknowledgement of the receipt ofthe first payload from the second device, the second TCP packet to thesecond device.

Still referring to FIG. 3C, and now in more detail, at step 348, a firstpacket to be transmitted using an unreliable transport protocol isreceived by a first device 105. In some embodiments, the packet isintended to be transmitted using a lossy protocol of UDP. In furtherembodiments, the packet comprises RDP over UDP. In other embodiments,the first packet is generated by an application program 338 executing inuser mode 332. In some embodiments, the packet is generated by anapplication 338 executing in kernel mode 334. In other embodiments, thefirst packet is received by the first device 105 for retransmission. Instill other embodiments, the first packet is intercepted by a filterprocess 322 before it reaches the network stack 310 a-310 b. The filterprocess 322 may execute in user mode 332 or in kernel mode 334. In someembodiments, the filter 322 is a mini-driver. In other embodiments, thefilter 322 is an NDIS driver. In other embodiments, the filter 322process uses application hooking to intercept the first packet. Infurther embodiments, the application hooking is implemented via anapplication programming interface (API). In one embodiment, the hookingof network packets occurs at the network layer of the network stack 310a-310 n.

At step 350, the first device 105 creates a first TCP packet including afirst payload of the received first packet and a first TCP header ofinformation associated with a TCP connection established between thefirst device 105 and a second device. For example, the TCP connectionmay be established between the client 105 and a peer computing device102 b in one embodiment, and between the client 105 and the gateway 340in another embodiment. In some embodiments, the first device 105indicates that the TCP packet contains a payload of packets constructedto be transmitted via a lossy protocol by opening a specific TCP port.In other embodiments, the first device 105 indicates that the TCP packetcontains a payload of packets constructed to be transmitted via a lossyprotocol by setting a flag in the TCP header. The TCP header may includeinformation regarding the source node, information regarding thedestination node, or a sequence number particularly identifying the TCPpacket.

At step 352, the first device 105 transmits the first TCP packet to thesecond device. In some embodiments, the second device may be a gateway340. In other embodiments, the second device is a “peer” computingdevice 102 b. The first TCP packet may be encrypted before transmissionto the second device using, for example, SSL or TLS.

At step 354, the first device 105 receives a second packet to betransmitted using an unreliable transport protocol, such as UDP. Thesecond packet may be received from the same application 338 thatgenerated the first packet. At step 356, the first device 105 createssecond TCP packet including a second payload of the received secondpacket and the first TCP header information, as described above. At step358, the first device 105 then transmits, before receipt of anacknowledgement of the receipt of the first payload from the seconddevice, the second TCP packet to the second device. In some embodiments,when an acknowledgment is received from the second device, the firstdevice 105 updates the TCP header information before transmitting thepacket. In other embodiments, the first device 105 creates a third TCPpacket with updated TCP header information and having the secondpayload. The first device then transmits the third TCP packet.

Upon receipt of the TCP packet, the second device decrypts it, ifnecessary, and determines that the payload is one or more packetsconstructed to be transmitted using a lossy protocol. The second devicemay determine this based on the port on which the packet was received orby a flag in the TCP header information. Once determined, the seconddevice strips the TCP header from the payload and delivers the payload.

In another aspect, the present invention is related to adjusting thereported maximum transmission unit (MTU) parameter to optimize networkcommunications by reducing packet fragmentation for encrypted networkpackets. This technique may be applied on one or both network stacks 310a-310 b of illustrative environment 300 of FIG. 3A. Encrypting a payloadof a network packet, such as any network packet processed according tothe illustrative method 360 described above, may increase the size ofthe payload. That is, the size of the network packet may increase toaccount for the change in size of the unencrypted original payload tothe encrypted payload.

Still referring to FIG. 3A, the network stacks 310 a-310 b may comprisea maximum transmission unit 402 a-402 b (MTU) parameter to indicate thesize of the largest unit of data that can be sent over a type ofphysical medium in a network, such as an Ethernet based network. In theembodiment of TCP/IP, the MTU 402 a-402 b indicates the largest datagramor packet than can be transmitted by an Internet Protocol (IP) layerinterface, without the interface needing to br4eak down or fragment thedatagram into smaller units. An MTU parameter 402 a-402 b may beassociated with a communications interface such as a network interfacecard. The default MTU size for Ethernet is 1,500 bytes, and IEEE 802.3is 1,492 bytes. As one ordinarily skilled in the art will recognize andappreciate, the default MTU size will be based on the networkingtechnologies such as Token Ring, FDDI, X.25, etc.

Referring now to FIG. 4, a flow diagram depicts an illustrativeembodiment of the MTU adjustment method 400 of the present invention. Inbrief overview, at step 405, a session between computing devices isestablished, such as between a first computing device 102 a and a secondcomputing device 102 b. At step 410, one of the computing devices 102,such as the first computing device 102 a, detects a network packethaving an encrypted payload. At step 415, the computing device 102 a-120b determines a setting for the MTU 402 a-402 b parameter of the networkstack 310 a-310 b to account for the size of the encrypted portion ofthe payload. At step 420, the MTU 402 a-402 b parameter is decreased toaccount for the encrypted portion. If the MTU 402 a-402 b is requestedor reported, the MTU 402 a-402 b will indicate a size smaller than theMTU size associated with the physical layer, such as 1,500 for Ethernet.

Using this technique, any device on the network 104 may communicatenetwork packets to the network stack 310 a-310 b according to thedecreased MTU size that can be encrypted along the route to the networkstack 310 a-310 b and not be fragmented. If the network packet isencrypted it should still fit in the actual MTU size of the physicalnetwork layer medium, such as Ethernet. For example, the MTU parameter402 a-402 b may be set to the default MTU size of 1,500 for Ethernet andin accordance with the illustrative method 400 decreased by a determinednumber of bytes, for example 100, to account for encryption overhead. Anetwork packet may be transmitted from a server resource to the clientcomprising a size equal to the reported MTU 402 a-402 b size of 1,400.The network packet may traverse the gateway 340 and get encrypted viathe SSL tunnel, which in turns increases the network packet size to1,475. Since this size fits into the MTU size of the Ethernet physicalmedium, the network packet will not be fragmented.

At step 405 of illustrative method 400, any type and/or form ofcommunication session between a first computing device 102 a and asecond computing device 102 b, such as client 105 b or gateway 340 ofFIG. 2A, may be established. In some embodiments, the session isestablished using the remote access client 120 on a first computingdevice. In one embodiment, the remote access client 120 establishes asession with the gateway 340, such as an SSL VPN session, or to anotherremote access client 120 on a peer computing device 102 b.

In some embodiments of step 410, the remote access client 120 detects anetwork packet having an encrypted payload. In one embodiment, thepacket capture mechanism 365 intercepts network packets and the agent326 determines if the packet is encrypted. However, any other portion ofthe remote access client 120, such as the filter 322 or frame monitor360 may determine if the packet is encrypted. In one embodiment, theentire payload of the network packet is encrypted, while in otherembodiments, a portion of the payload is encrypted. The presentinvention may use any type and/or form of means or mechanism fordetermining if a packet has encryption. For example, in some cases, theremote access client 120 may check for a flag or field of the networkpacket indicating the payload is encrypted. In other embodiments, theremote access client 120 may check whether any portion of the payload isunintelligible, because it contains random data or noise fromencryption. Additionally, the encrypted payload may be encrypted inassociation with any layer of the network stack 310 a-310 b, such aslayer 2, 3, 6 or 7 encryption.

In some embodiments of step 415, the illustrative method 400 of thepresent invention determines the adjustment to the reported MTU 402a-402 b size on a packet by packet basis, or in other embodiments, on aconnection or session basis, and at step 420 adjusts the MTU 402 a-402 baccordingly. In one embodiment, the MTU 402 a-402 b is decreased exactlyby the amount of encryption overhead for the network packet. In somecases, the illustrative method 400 determines the MTU 402 a-402 b sizeadjustment once for the entire session or connection and decreases thesize of the MTU 402 a-402 b to a value to account for encryptionoverhead for the entire session. For example, although network packetsmay have varying encryption overhead, the adjustment accounts for thelargest encryption overhead. In further embodiments, the MTU 402 a-402 bmay be adjusted to take into consideration encryption that may occurwhen the network packet leaves the network stack 310 a-310 b, such asencryption by a gateway 340 that may occur in the end-to-end networktraversal of the network packet

Additionally, the MTU 402 a-402 b size may be adjusted for other networkperformance factors in addition to the encryption overhead. In someembodiments, although the MTU 402 a-402 b is decreased due to encryptionoverhead, it may be further decreased to account for other overhead andfactors related to network communication, as well as increased in othercases. For example, the MTU 402 a-402 b may have been previouslyadjusted for a factor not related to encryption and after using thetechniques of the present invention the MTU 402 a-402 b is decreased totake into account encryption overhead. One ordinarily skilled in the artwill recognize and appreciate that there may be other factors andconsiderations for adjusting the MTU besides or in addition to adjustingfor encryption overhead in accordance with the techniques of the presentinvention.

Referring now to FIGS. 5A and 5B, the present invention, in anadditional aspect, is related to client-side application-aware networkcommunication prioritization techniques. The remote access client 120 ofthe present invention provides for the intelligent and client centricprioritization of application network communications on a client basedon the type and/or priority of an application. As depicted in the system500 of FIG. 5A, the remote access client 105 of computing device 102 isconnected to network 104. The client 105 may execute one or moreapplications 338 a-338 n, which access the network 104 via the agent 326and filter 322 of the remote access client 120. In some embodiments, theapplications 338 a-338 n provide one or more real-time datacommunications, such as VoIP. In other embodiments, one or more of theapplications 338 a-338 may provide email, collaboration, online meeting,and/or desktop sharing related services or functionality.

As illustrated in FIG. 5A, the packet capture mechanism 365, 365′ may beincluded in the filter 322 or the agent 326 of the remote access client120, for intercepting network traffic of any of the applications 338a-338 n of the client 105. The remote access client 120 may comprise anyqueues 540 a-540 n for queuing and prioritizing network communicationsof the client 105. In one embodiment, the queues 540 a-540 n may beincluded in a network driver, such as an NDIS driver for the filter 322,and in other embodiments, may be included with or accessible by theagent 326. The queues 540 a-540 n may comprise any type and/or form ofsuitable means and/or mechanisms for storing and/or arranging networkpackets, such as network packets intercepted by the packet capturemechanism 365. In some embodiments, the queues 540 a-540 n may beassociated with or assigned to network packets related to applications338 a-338 n of the client 105. In other embodiments, the queues 540a-540 n may be organized by levels of priority, such as high, medium,low, or numerically such as priority 1 . . . 10. One ordinarily skilledin the art will recognize and appreciate that number of queues 540 a-540n may be based on any desired granularity of prioritization, such as 3,5 or 10 levels of priority. Additionally, some of the queues 540 a-540 nmay be used for receiving and/or transmitting network packets prior tobeing placed into and/or taken out of a priority based queue 540 a-540n.

The remote access client 120 may also have, access, or use a routingtable 538 for determining how to route network packets of the client viathe agent 326, such as onto the network 104 via a gateway 340. In oneembodiment, the agent 326 establishes and maintains an SSL VPNconnection to the gateway 340, such as illustrated in FIG. 1A forexample. In one embodiment, the routing table 538 comprise informationabout a source computing device and a destination computing device toidentify a communication path or connection between a source anddestination communication points. The routing table 538 may include asource IP address and source port, and an destination IP address anddestination port to identify a communication path on the network 104.For example, the source IP address and source port may represent the IPaddress of the client 105 and the port by which an application 338 a-338n on the client 105 communicates on the network 105. The destination IPaddress may represent the IP address of a peer computing device to whichthe application 338 a-338 n communicates with via the destination portused by the peer device.

Additionally, the remote access client 120 may have one or more policies520 for specifying client-side prioritization of network communicationsrelated to applications 338 a-338 n running on application. Thesepolicies 520 may be specified by any suitable means and/or mechanisms.In some embodiments, the policies 520 may be specified by the name ofthe application 338 a-338 n and/or the type of application 338 a-338 n.In other embodiments, the policies 520 may be specified in accordance tothe type of one or more protocols used by the applications 338 a-338 nand/or the size of the payload of the network packet. In anotherembodiment, the policies 520 define prioritization based on whether anapplication is running in the foreground or the background of the client105. In yet another embodiment, policies 520 may indicate prioritizationbased on the destination network address, such as host name or IPaddress, and/or destination port number. Additionally, the policies 520may be specified hierarchically to account for multiple applications 338a-338 n and/or multiple protocols that may be executed on the client 105at any point. Furthermore, the policies 520 may be specifiedconditionally, such as if one application 338 a is running, a secondapplication 338 b may have a higher or lower priority. One ordinarilyskilled in the art will recognize and appreciate the multitude of waysto define client-side application priorities.

The policies 520 may be accessible by the agent 326, configured into theagent 326, or loaded by the agent 326. For example, the policies 520 maybe provided by or downloaded via the gateway 340. The policies 520 maycomprise any type and format of syntax and/or language for specifying apolicy, and may be provided via any type and/or form of medium, such aselectronically by one or more network packets or via a file, such as anXML file. The policies 520 may be configurable by a user by any suitablemeans and/or mechanism. For example, the agent 326 may provide aconfiguration mechanism such as a user interface, graphical orotherwise, design and constructed for configuring or specifying thepolicies 520.

In view of the system 500 of FIG. 5A and FIGS. 1A-1C, the prioritizationtechnique of the present invention illustrated by method 550 in FIG. 5Bwill be described. In brief overview, at step 555 of the illustrativemethod 550, the client 105 intercepts one or more networks packetsassociated with an application 338 a-338 n on the client 105, and, atstep 560, the network packets are stored to a queue 540 a-540 n. At step565, a priority for the intercepted and queued network packet isdetermined based on the type and/or priority of the application 338a-338 n. At step 570, the determined priority is indicated for thenetwork packets, and, at step 575, the network packets are communicatedaccording to the determined priority. As such, the outbound networkpackets generated by an application 338 a-338 n on the client 105 areprioritized by the client 105 prior to transmission based on the typeand/or priority of the application 338 a-338 n. For example, theapplication 338 a may generate real-time data of VoIP communications,such as RTP over UDP via a TCP/IP session of an SSL connection to thegateway 340. The client 105, using the techniques of the presentinvention, may prioritize the real-time data communications ofapplication 338 a ahead of other applications, such as non-real-timedata communication applications. This technique may compliment Qualityof Service (QOS) networks where network traffic prioritization occurs inintermediary network devices, such as switches and routers.

At step 555 of illustrative method 500, the client 105 may interceptnetwork packets of one or more applications 338 a-338 n transparently tothe application 338 a-338 n, the gateway 340, a peer computing device,and any of the network layers of a network stack. In this manner, thetechniques of the present invention support any type of application 338a-338 n on the client 105. In some embodiments, the network packets areintercepted by the packet capture mechanism 360 via agent 326 or filter322. Any inbound and/or outbound network packets of an application 338a-338 n may be intercepted by the remote access client 120 of thepresent invention.

At step 560, the network packets intercepted at step 555 may be storedin a queue 540 a-540 n. In one embodiment, the network packet is storedto a temporary queue 540 a-540 n prior to prioritizing the networkpacket at steps 565 and 570. In other embodiments, the network packet isstored to a determined priority queue 540 a-540 n or a queue 540 a-540 nassociated with an application 338 a-338 n after the network packet isprioritized at steps 565 and/or step 570.

At step 565, the remote access client 120 of the present determines theassociation of network packets with applications 338 a-338 n in order todetermine priorities and apply any priority based policies 520. Theclient 105, such as via agent 326, can associate network traffic withapplications 338 a-338 n by any suitable means and/or mechanisms. Insome embodiments, the agent 326 identifies the network packet asgenerated from an application 338 a-338 n by any of the content of thenetwork packet, such as any headers, fields, or the type and content ofdata in the payload of the network packet. In other embodiments, anetwork packet is associated with an application 338 a-338 n by matchinginformation from the routing table 538, such as source and destinationIP addresses and ports numbers with the IP addresses and ports numbersof the network packet. In some embodiments, the agent 326, such as viathe frame monitor 360, may perform a checksum on the packet to verifythat the identified application actually generated the packet.

Additionally, the remote access client 120 may determine whether theapplication 338 a-338 n associated with the network packet is running inthe foreground or the background of the client 105. Furthermore, theremote access client 120 may determine any priorities, such as processtask priority, assigned to the application 338 a-338 n by the operatingsystem of the client 105. In other embodiments, the remote access client120 may determine any other characteristics or statistics of theapplication 338 a-338 n such as size, memory usage, total executiontime, and/or frequency of use. One ordinarily skilled in the art willrecognize and appreciate the various characteristics of an applicationthe present technique may use for providing client-sideapplication-aware network communication prioritization.

At step 570, the remote access client 120 of the present inventionindicates a priority for intercepted and queued network packets based onthe application 338 a-338 n associated with the packet at step 565. Inone embodiment, the agent 326 uses the policies 520 to apply a priorityto network packets of applications 338 a-338 n in accordance with theprioritization rules specified or indicated by the policies 520. In someembodiments, the agent 326 may use characteristics of the application338 a-338 n, such as running in the foreground or background, toindicate priority for a network packet of the application 338 a-338 n.In other embodiments, the agent 326 may use any combination of thepolicies 520 and characteristics of the application 338 a-338 n toindicate a priority for the network packets of the application 338 a-338n.

In some embodiments, the agent 326 indicates the priority to the filter322 for management of network packet queues 540 a-540 n to apply theindicated priorities. The agent 326 may communicate the priority ofnetwork packets to the filter 322 by any suitable means and/or mechanismsuch as via an application programming interface (API), such an IOCTLinterface, or any other type and/or form of interface known to thoseordinarily skilled in the art. In one embodiment, the filter 322 is notaware of the application 338 a-338 n by name but can associatepriorities to network packets of applications 338 a-338 n via therouting table 538. An application 338 a-338 n corresponding to a networkpacket can be identified by any combination of source and destinationidentifiers, such as IP addresses and port numbers. As such, in someembodiments, the agent 326 indicates priorities to the filter 322 byrouting information instead of application name. In other embodiments,the agent 326 provides to the filter 322 a mapping between applications338 a-338 n, such as by application name or process id, to the routinginformation in a routing table 538.

Based on the indicated priorities for applications 338 a-338 n, in someembodiments, the filter 322 may place, arrange, or coordinate networkpackets into queues 540 a-540 n in support of the priorities. In oneembodiment, the filter 322 may move network packets from temporaryqueues 540 a-540 n or from memory or other storage to a queue 540 a-540n associated with the application 338 a-338 n, a queue 540 a-540 nassociated with a priority, or a queue 540 a-540 n associated with bothan application and a priority. For example, in one embodiment, all highpriority network traffic may be placed in a high priority queue 540 aand arranged in order based on an order of priority of the application338 a-338 n, such as real-time data applications 338 a-338 n prior toother applications 338 a-338 n. In some embodiments, the network packetsmay be arranged in order in a priority queue 540 a-540 n based on thetime the network packet was intercepted by the packet capture mechanism365, such as in a FIFO manner. In yet a further embodiment, one queue540 a-540 n may be used or prioritization by the filter 322. Eachnetwork packet may be placed and arranged in a priority order respectiveto all other intercepted network packets to provide a packet by packetprioritization across all applications 338 a-338 n and interceptednetwork packets. One ordinarily skilled in the art will recognize andappreciate that the network packets may be arranged in various priorityqueues 540 a-540 n, such as high, medium, low, or by any othergranularity, and be placed or arranged in the queue in any suitablemanner in practicing the operations of the present invention describedherein.

In one embodiment, all network packets for an application 338 a-338 nare placed in a queue 540 a-540 n associated with the application 540a-540 n. For example, intercepted network packets for an applicationcommunicating to a first destination IP address, and a first destinationport may be placed in a first queue 540 a. In another embodiment, allnetworks packets for a type of application 338 a-338 n, such as an emailor voice application, or all network packets for a type of protocol usedby the application 338 a-338 n, such as RTP or UDP, may be placed in aqueue 540 a-540 n for prioritizing networks packets for one or moreapplications. For example, online collaboration related applications 338a-338 n may be placed and prioritized in a first queue 540 a forcollaboration related applications. A second queue 540 b may be used foremail related applications 338 a-338 n. In another example, a queue 540a may be used for applications 338 a-338 n communicating real-time dataor communicating using the RTP and/or UDP protocol. In a furtherexample, a queue 540 a may be used for applications 38 a-338 ncommunicating using a remote display protocol, such as ICA or RDP.

Within each application associated queue 540 a-540 n organized byspecific application 338 a-338 n, type or category of application 338a-338 n, or by protocol, the network packets ay be further prioritizedby the characteristic of the application 338 a-338 n generating them,e.g., a foreground application, the size of the network packet, or thetime the network packet was intercepted. In some embodiments, one ormore queues 540 a-540 n may be used for network packets intercepted butnot prioritized because a policy 520 does not exist or apply to thenetwork packet, or the policies 520 indicate to ignore or not processthe network packet for prioritization. One ordinarily skilled in the artwill recognize and appreciate the various ways network packets may beplaced and arranged in a priority based manner in queues 540 a-540 nassociated with the application 338 a-338 n, the type of application 338a-338 n or the protocol used by the application 338 a-338 n, and thatthe priority may be based on the policies 520 specified for the client105.

At step 575 of illustrative method 550, the network packets arecommunicated from the queues 540 a-540 n according to the determinedpriorities for the network packets. In some embodiments, the networkpackets are organized into priority queues 540 a-540 b so that thenetwork packets of the highest priority queue 540 a-540 n arecommunicated first, and then the next highest priority queue 540 a-540 nsecond, and so on. In other embodiments, the queues 540 a-540 n areorganized by application 338 a-338 n, and therefore, at step 575, thepresent invention communicates network packets from the queue 540 a-540n based on the respective priorities of the applications 338 a-338 n.Regardless of the queue 540 a-540 n organization and management, oneordinarily skilled in the art will recognize and appreciate that theremote access client of the present invention will communicate thenetwork packets from the queues in a manner according to or consistentwith the determined priorities, which in turn, may be based or derivedfrom the policies 520 of the client.

In some embodiments, the remote access client 120 of the presentinvention considers other network factors in determining what networkpackets to communicate from what queue. For example, the remote accessclient 120 may receive an indication of network congestion, such asreceiving a window size of zero for a TCP connection related to anapplication 338 a-338 n. In another example, the remote access client120 may recognize a high number of retransmits to a particulardestination. As such, in some embodiments, the remote access client 120may throttle back or not communicate network packets related to othernetworks factors, such as congestion, even though the network packetsmay have a higher priority than other network packets in a queue 540a-540 n. Thus, the client 105 controls and manages the prioritization ofnetwork communications of the client 105 on an application 338 a-338 nbasis and in accordance with any policies 520 for the client 105 and infurther view of any network statistics and other factors occurring onthe network.

In yet a further aspect and referring now to FIGS. 6A and 6B, thepresent invention is related to providing a network disruption shieldingtechnique for persistent and reliable connectivity. FIG. 6A illustratesenvironment 300 as discussed above in conjunction with FIG. 3A. Theenvironment 300 illustrates network stacks 310 a and 310 b, which mayrepresent network stacks of computing devices 102 a-120 b or gateway340, such as any of the computing devices 102 and the gateway 340illustrated in FIGS. 1A-1C, 2A, or 5A. Each network stack 310 a-310 bmay comprise one or more networks layers, such as a TCP/IP network layeron top of the frame network layer as one ordinarily skilled in the artwill recognize and appreciate. Although the network stacks 310 a-310 bare illustrated in environment 300 of FIG. 6A with a certain set ofnetwork layers, one ordinarily skilled in the art will recognize andappreciate that the network stacks 310 a-310 b may have any type and/orform of network layers, in any suitable combination, and each of thenetwork stacks 310 a-310 b may have different forms of each layer inrelation to the other network stack.

The network stacks 310 a-310 b may be considered to have a first portion605 a-605 b of the network stack, and a second portion 610 a-610 b ofthe network stack. As illustrated in the example network stacks 310a-310 b of FIG. 6A, the first portion 605 a-605 b of the network stackcomprises the network layers at and below the TCP network layer. Thesecond portion 610 a-610 b may comprise those network layers above theTCP network layer, such as a UDP over SSL protocol layer. Although thefirst portion 605 a-605 b and the second portion 610 a-610 b are shownas portioned, segmented, or otherwise divided at the TCP layer, thefirst portion and second portion may be formed at a higher or lowerdividing layer in practicing the network disruption shielding techniqueof the present invention as one ordinarily skilled in the art willrecognize and appreciate.

The network stacks 310 a-310 b illustrated in FIG. 6A may represent anapplication 338 a-338 n on client 105, such as the client depicted inFIG. 5A, establishing a peer-to-peer SSL VPN connection to a secondcomputing device 102 b or, alternatively, a gateway 340. The client 105may be a mobile client, such as a notebook, personal digital assistant(PDA), a smart phone, or any type of mobile computing ortelecommunication device. The client 105 may communicate real-time datasuch as VoIP communication via the UDP protocol or RTP over UDP via theSSL session established to the peer device 102 b or gateway 340. In oneembodiment, the agent 326 of the remote access client 120 establishesand maintains the SSL or SSL VPN session to the gateway 340 or to peercomputing device 102 b. The agent 326 may operate in user-mode 332, andmay handle any network layer and protocol processing related to thesecond portion 610 a-610 b of the network stack 310 a-310 b, along withany application layer protocols. As a TCP/IP based network 104, the UDPover SSL session of the second portion 610 a-610 b of the network stack310 a-310 b may be communicated over a TCP/IP stack forming the firstportion 605 a-605 b of the network stack 310 a-310 b. In view of theremote access client 120 of the present invention, such as illustratedin FIG. 1A or 5A, the filter 322 may be a network driver operating inkernel-mode 332 within the first portion 605 a-605 b of the networkstack 310 a-310 b.

The present invention uses a network disruption shielding technique asdepicted by illustrative method 650 in FIG. 6B to maintain the secondportion 610 a-610 b of the network stack 310 a-310 b through a networklevel connection interruption, such as any type and/or form of networkdisruption to the first portion 605 a-605 b of the network stack 310a-310 b. The network disruption shielding technique of the presentinvention may be performed transparently to an application 338 a-338 nof the client 105, a user of the client 105, any one or more networklayers above the first portion 605 a-605 b, and the gateway 340 or peercomputing device 102 b, and any portion of their respective networkstacks 310 a-310 b. In one embodiment, the network disruption isshielded without notification to the user of the client that the networkwas disrupted or a session was interrupted.

In brief overview of illustrative method 650, at step 665, a client 105establishes a session via at least a first protocol over a networkconnection between the client and another device, such as a peercomputing device or gateway. As such, a network stack 310 a-310 b isestablished or used on the client 105. The network stack 310 a-310 b hasa first portion 605 a-605 b and a second portion 610 a-610 b. At step660, a disruption in the network connection is detected causing thefirst portion 605 a-605 b of the network stack 310 a-310 b to bedisestablished, or otherwise disrupted from being used or continued tobe used. At step 665, the present invention maintains the second portion610 a-610 b of the network stack 310 a-310 b during the disruption andmaintaining a session, or sessions, associated with the network layersof the second portion 610 a-610 b.

During the disruption, at step 670, any network packets related to thesecond portion 610 a-610 b of the network stack 310 a-310 b may bequeued. At step 675, the first portion 605 a-605 b of the network stack310 a-301 b is reestablished or otherwise received from the networkdisruption. While the first portion 605 a-605 b of the network stack 310a-301 b is reestablished, the present invention maintains the secondportion 610 a-610 b, and sessions thereof, allowing at step 680, tocontinue with the session by linking or re-associating the secondportion 610 a-610 b with the first portion 605 a-605 b of the networkstack 310 a-310 b. The network connection and/or the session mayautomatically be re-authenticated at step 680. At step 685, theillustrative method may communicate any queued network packets andcontinue with the session transparently as if the network disruption didnot occur.

In an embodiment of illustrative step 655, a first computing device 102a may establish a network connection with a second device, such as apeer computing device 102 b or a gateway 340, by any suitable meansand/or mechanism and using any type and/or form of connection basedprotocol. For example, the network connection may be established via aTCP connection on a TCP/IP network or by an SPX connection on an IPX/SPXnetwork. In some embodiments, the network connection may be initiated byany of the applications 338 a-338 n on the client, such as anyapplication illustrated in FIG. 5A. For example, a remote displayclient, such as an ICA client of Citrix Systems, Inc. or a RemoteDisplay Client of Microsoft Corporation may initiate or establish thenetwork connection. In other embodiments, the network connection ofillustrative step 665 may be initiated and/or established via the agent326, filter 322, or any other portion of the remote access client 120.In one embodiment, the establishing of the network connection forms thefirst portion 605 a-605 b of the network stack 310 a-310 b. In otherembodiments, the first portion 605 a-605 b of the network stack 310a-310 b, or portion thereof, is established via connection to a network104 upon startup of the client 105.

In some embodiments, the second portion 610 a-610 b of the network stack310 a-310 b is formed by establishing one more sessions, such as an SSLsession, via any type and/or form of protocol over the networkconnection, such as a remote display protocol of ICA or RDP. The sessionmay be established via any application 338 a-338 n or the remote accessclient 120 of the client. In one embodiment, the session may correspondto a tunneling or gateway session with a peer computing device 102 b ora gateway 340. In another embodiment, the session may be any type ofinteractive session such as a media session established via a signalingprotocol, SIP for example. For example, the session of the secondportion 610 a-610 b of the network stack 310 a-310 b may comprise a VoIPcommunication session, such as one established by illustrative method260 of FIG. 2B. Additionally, there may be multiple sessions associatedwith the second portion 610 a-610 b of the network stack 310 a-310 b.For example, an SSL or SSL VPN session may form one session, while asecond session, such as media session via RTP over UDP may form a secondsession. Additionally, at any application layer of the network stack 310a-310 b one or more applications 338 a-338 n on the client 105 mayestablish an application level session with a peer computing device 102b. In one embodiment, the agent 326 of the remote access client 120 isresponsible for establishing and maintaining the second portion 610a-610 b of the network stack 310 a-310 b and one or more of theassociated sessions.

At step 660 of the illustrative method 650 of the present invention, adisruption is network connection is detected. In one embodiment, thenetwork disruption may be caused by a mobile client 105 roaming betweennetworks and networks segments, which, in some embodiments, causes theclient 105 to obtain a new network IP address and/or host name. In someembodiments, the disruption disrupts the first portion 605 a-605 b ofthe network stack 310 a-30 b, such as, for example, causing a TCP or SPXconnection to be disconnected. In one aspect, the disruption causes thefirst portion 605 a-605 b, or any portion thereof, of the network stack310 a-310 b to be disestablished, or otherwise needing to bere-established, reconnected, reconfigured or rebuilt. For example, insome embodiments, the IP layer of the network stack may maintain intactwhile the TCP layer is reestablished. In one embodiment, any TCP relateddrivers may need to be re-started. In other embodiments, the TCP/IPlayer be intact even though the network connection is disrupted, andonly a new TCP connection needs to be established. In other embodiments,the TCP/IP layer is intact but needs to reconfigure itself for a newnetwork or network segment, such as changing the IP address of theclient 105. One ordinarily skilled in the art will recognize andappreciate the various ways a network connection may be disrupted andimpact or affect a first portion of the network stack.

In some embodiments, the agent 326, or any other portion of the remoteaccess client 120 may detect the network disruption by any suitablemeans and/or mechanisms. In one embodiment, the agent 326 may determinea network disruption by receiving an error message or failure uponcalling or executing an API call to the first portion 605 a-605 b of thenetwork stack 310 a-310 b. For example, the SSL session maintained bythe agent 326 for the second portion 610 a-610 b relies or depends onthe TCP connection of the first portion 605 a-605 b of the network stack310 a-310 b. As the agent 326 transacts via the SSL session, the agent326 may receive an error or failure message indicating a problem withthe TCP connection. In other embodiments, the agent 326 may receive anevent or message from any network layer of the first portion 605 a-605 bof the network stack 310 a-310 b indicating a network disruption. Oneordinarily skilled in the art will recognize and appreciate the variousways the network disruption may be detected.

At illustrative step 665, in some embodiments, upon detection of thenetwork disruption, the agent 326 or any other portion of the remoteaccess client 120 of the present invention maintains the second portion610 a-601 b of the network stack 310 a-310 b during the disruption. Forexample, although the SSL based session maintained by the agent 326depends on an underlying TCP connection, the agent 326 keeps the SSLsession open or active through the disruption to the TCP connection. Asthere may multiple sessions associated with one or more layers of thesecond portion 610 a-610 b of the network stack, the agent 326, in someembodiments, keeps one or more, or all, of the multiple sessions open oractive although the first portion 605 a-605 b of the network stack 310a-310 b is disrupted.

At step 670 of illustrative method 650, the remote access client 120 ofthe present invention, in some embodiments, queues one or more networkpackets of any of the protocols related to the second portion 610 a-610b of the network stack 310 a-310 b during the network disruption. Theremote access client 120 may use any type and/or form of queuingmechanisms, such as any of the queues 540 a-540 n illustrated in FIG.5A. In other embodiments, the remote access client 120 may discardnetwork packets during the disruption, such any packets related to alossy protocol, such as RTP over UDP for voice communications. In somecases, it may be desirable to discard packets, such as UDP packets, toreduce latency and quality issues, such as in voice communications. Infurther embodiments, the remote access client 120 may queue some networkpackets and discard other network packets. In an additional embodiment,the remote access client 120 may queue the network packets, and discardsome or all of the network packets after a predetermined period of time.The remote access client 120 may use the policies 520 to determine whichnetwork packets to queue and/or discard. For example, a network packetof a first application 338 a may be queued while a network packet of asecond application 338 n is discarded. In other embodiments, the remoteaccess client 120 may use any network statistics or any network trafficinspection techniques, for example stateful inspection, as known tothose skilled in the art to determine whether to queue and/or discardnetwork packets during the disruption.

At step 675 of illustrative method 650, the first portion 605 a-605 b ofthe network stack 310 a-310 b is reestablished while the second portion610 a-610 b of the network stack 310 a-310 b is maintained along withmaintaining any desired session or sessions of the second portion 610a-610 b of the network stack 310 a-310 b. The first portion 605 a-605 bof the network stack 310 a-310 b may be reestablished by any suitablemeans and/or mechanisms. For example, the client 105 may reestablish theTCP/IP connection to the network 104, such as by logging into a newnetwork for a roaming mobile client 105. In other embodiments, theremote access client 120, such as via the agent 326 or the filter 322,reestablishes the first portion 605 a-605 b of the network stack 310a-310 b. For example, the agent 326 may initiate and establish a new TCPconnection. Upon reestablishing the first portion 605 a-605 b, thesecond portion 610 a-610 b of the network stack 310 a-310 b is linkedwith, re-associated with or starts to use or continue to use the firstportion 605 a-605 b to reestablish the network stack 310 a-310 b. Insome embodiments, the agent 326 may be notified by an event of anynetwork layer that the first portion 605 a-605 b has been reestablishedor in other embodiments, may poll by any predetermined frequency todetermine the first portion 605 a-605 b is reestablished. For example,the agent 326 may check if the TCP connection is active or can bereconnected.

In some embodiments, at step 680, the remote access client 120, such asthe agent 326, may automatically re-authenticate the client 105 or auser of the client 105 for the network connection, such as a TCPconnection for the first portion 605 a-605 b of the network stack 610a-610 b. For example, the remote access client 120 may automaticallyre-authenticate the client 105 to a network 104 using any networkrelated credentials of a user of the client 105. Additionally, theremote access client 120 may automatically re-authenticate the client105 or a user of the client 105 for any session associated with thesecond portion 610 a-610 b of the network stack 310 a-310 b. Forexample, the SSL session between the agent 326 and the gateway 340 orpeer computing device 102 c may be re-authenticated.

In another example, an application 338 a may be accessing a hostservice, web server, or application server that uses authenticationcredentials for access. The agent 326 may automatically re-authenticatethe application 338 a to the corresponding service or server usingapplication related authentication credentials. In some embodiments, theremote access client 120 may re-authenticate the client and/or user ofthe client 105 at multiple levels, such as for network access and/or TCPconnection, SSL or SSL VPN session, and/or any application levelsessions, such as a media interactive user session, for example, a VoIPtelephone session. Furthermore, the remote access client 120 mayre-authenticate at any time prior to step 685, during step 685, forexample, after communicating queued network packets but beforecontinuing other communications, or after step 865, in response to arequest to authenticate from a peer computing device, such as a serveror the gateway 340.

At step 685 of illustrative method 650, the remote access client 120 ofthe present invention continues to use the session or sessions of thesecond portion 610 a-610 b of the network stack. If any network packetshave been queued or remain queued at step 670, the remote access client120 communicates the queued network packets and continues communicatingany network packets of the client 105, such as network packets generatedby or sent to the one more applications 338 a-338 n of the client 105.As such, the network disruption shielding technique of the presentinvention provides a seamless and transparent solution to nomadic mobilecomputing solutions and for generally providing reliable and persistentnetwork connectivity and access.

In the example of a VoIP communications, the illustrative method 650 ofthe present invention will reduce the number of telephone call drops dueto network disruptions and improve the usage of and experience withVoIP. A VoIP user will not need to reconnect the telephone call due totemporary network disruptions in network availability as the remoteaccess client 120 of the present invention will automatically maintainthe session and reconnect to the network. Additionally, the remoteaccess client 120 of the present invention will automaticallyre-authenticate the connection and sessions for providing security afterthe network disruption. Furthermore, the network shielding technique ofthe present invention is useful for 1) continuing transactions,commands, or operations automatically through the network disruption, 2)maintaining session related context and cache through the networkdisruption, and 3) automatically handling change in network address ofthe client due to changes in the network.

By providing a reliable and persistent connection, the present inventionalso avoids interruptions to transactions, commands or operations aspart of the functionality exercised between the a first computing device102 a and a second computing device 102 b, such as client 105 a and 105b in FIG. 1C. For example, a file copy operation using Windows Explorerhas not been designed to continue working after there is a disruption ina network connection. A user on the client 105 may use the file copyfeature of Windows Explorer to copy a file from the client 105 to aserver 102 c. Because of the size of the file or files, this operationmay take a relatively extended period of time to complete. If during themiddle of the operation of the copy of the file to the server, there isan interruption in the network connection between the client 105 and theserver, the file copy will fail. Once the network connection isre-established, the user will need to start another file copy operationfrom Windows Explorer to copy the file from the client 105 to theserver. Under the present invention, the user would not need to startanother file copy operation. The network connection would bere-established in accordance with the network disruption shieldingtechnique of the present invention as illustrated in FIG. 6B. As such,the file copy of Windows Explorer would not get notified of theinterruption in the network connection and therefore, would not fail.The remote access client 120 would re-establish any connections andtransmits any queued data so that operation can continue withoutfailure. The remote access client 120 would maintain a queue of the datarelated to the file copy operations that has not been transferred to theserver because of the interruption in the network connection. Once thenetwork connection is re-established, the remote access client 120 cantransmit the queued data and then continue on with transferring the datarelated to the file copy operation in due course.

Although this aspect of the invention is described in terms of a filecopy operation example, one ordinarily skilled in the art will recognizethat any operation, transaction, command, function call, etc. transactedbetween a first computing device 102 a and a second computing device 102b, can be maintained and continued without failure from the networkconnection disruption, and, furthermore, without the client 105 or userof the client 105 recognizing there was a disruption or having notice ofthe disruption. Additionally, the transaction or operation can bemaintained and continued transparently to the application 338, thegateway 340, second computing device 102 c, and any part of the secondportion 610 a-610 b of the network stack 310 a-310 b.

By providing the client 105 with a reliable and persistent connection toa peer computing device 102 b or gateway 340, the present inventionavoids the process of opening a new user session with an application 338on the peer, such as a host service on server, by maintaining the usersession through network connection interruptions. For each user sessionbetween peer computing device, each computing device may maintainsession specific context and caches, and other application specificmechanisms related to that instance of the user session. For each newuser session established, these session specific context and caches needto be re-populated or re-established to reflect the new user session.For example, a user on the client 105 may have an http session with aserver 102 c having a web server or web application. The server 102 cmay keep context specific to providing this instance of the http sessionwith the client 105. The context may be stored in the memory of theserver, in files of the server, a database or other component related toproviding the functionality of the server 102 c. Also, the client 105may have local context specific to the instance of the http session,such as a mechanism for keeping track of an outstanding request to theweb server. This context may be stored in memory of the client 105, infiles on the client 105, or other software component interfaced with theclient 105. If the connection between the client 105 and the server 102c is not persistent, then a new user session needs to be establishedwith new session specific context on the server 102 c and the client105. The present invention maintains the session so that a new session,and therefore new specific session context, does not need to bere-established.

The present invention maintains the user session through network levelconnection interruptions and without notification to the user of theclient that the session was interrupted. In operation of this aspect ofthe invention, the client 105 establishes the connection to the peercomputing devices. Via the connection, a session between the client 105and the server is established. The remote access client 120 can storeand maintain any session related information such as authenticationcredentials, and client 105 and host server 102 c context for theestablished session. Upon detection of a disruption in networkconnection, the remote access client 120 can re-establish the firstportion 605 a-605 b of the network stack 310 a-301 b while maintainingthe second portion 610 a-610 b of the network stack. The networkconnection disruption may cause an interruption to the underlying TCP/IPconnection used by the session between the client 105 and the server 102c. However, since the second portion 610 a-610 b of the network stack310 a-310 b is maintained, the session can be re-established and/orcontinued after the network connection is re-established without theuser on the client 105 having notification that the session wasinterrupted. Thus, the interruption of the session caused by the networkconnection disruption is effectively hidden from the user using thenetwork disruption shielding techniques of the present invention.

Furthermore, by providing a reliable and persistent connection, thepresent invention also enables a client 105 to traverse throughdifferent network topologies without re-starting a session or anapplication 338 on the client 105. For example, the client 105 may be acomputer notebook with a wireless network connection. As the client 105moves from a first wireless network to a second wireless network, theclient's network connection may be temporarily disrupted from the firstwireless network as a network connection is established with the secondwireless network. The second wireless network may assign a new networkidentifier, such as a host name or internet protocol address, to theclient 105. This new network identifier may be different than thenetwork identifier assigned to the client 105 by the first wirelessnetwork. In another example, the client 105 may be physically connectedthrough an Ethernet cable to a port on the network. The physicalconnection may be unplugged and the client 105 moved to another locationto plug into a different port on the network. This would cause adisruption into the network connection and possibly a change in theassigned network identifier. Without the present invention, any sessionsbetween peer computing devices may need to be restarted due to thechange in the network topology, the disruption to the networkconnection, and/or the change in the assigned network identifier. By themethod and systems described herein, the remote access client 120 of thepresent invention maintains the network connection for the client andautomatically re-established the client's 105 network connectionincluding handling changes in the network topology and networkidentifier. The client 105, and any applications or sessions on theclient 105, can continue to operate as if there was not a networkconnection disruption or a change in the network identifier.Furthermore, the user on the client 105 may not recognize there were anyinterruptions or changes, and the client 105 may not receive any noticeof such interruptions.

In an additional aspect, any of the techniques of the present invention,such as the illustrative methods of FIGS. 2B, 3B, 3C, 4, 5B and 6B, canbe practiced in one or more combinations with each other. In oneembodiment, the peer-to-peer routing technique may be practiced with thefalse acknowledgement and/or MTU adjustment techniques. This wouldprovide a client communicating real-time data, such as VoIP, to connectto the peer via a more optimal and direct route and to communicate thereal-time data via UDP over a secure SSL/TCP/IP connection, whileavoiding any latency due to any reliability mechanism of TCP and reducefragmentation due to the encryption overhead. Additionally, thisembodiment may be further combined with the client-sideapplication-aware prioritization technique and/or the network disruptionshielding technique. As such, the secure real-time data communicationscan be communicated from the client at higher priorities than otherapplications of the client to improve the quality of the real-timeexperience, such as VoIP. The network disruption technique would allow amobile VoIP phone, such as a soft phone of a notebook, roam betweennetwork access points and automatically continue with the session.

The techniques of the present invention are complimentary to each otherfor network communication optimizations, such as for example in VoIPcommunications over a SSL VPN gateway. As such, each of the 1)peer-to-peer routing technique, 2) the false acknowledgement technique,3) payload shifting technique, 4) the MTU adjustment technique, 5) theclient-side application-aware technique, and 5) the network disruptionshielding technique of the present invention may be practiced with oneor more of the following techniques and optimization of the presentinvention: 1) the peer-to-peer routing technique, 2) the falseacknowledgement technique, 3) payload shifting technique, 4) the MTUadjustment technique, 5) the client-side application-aware technique,and/or 5) the network disruption shielding technique.

In one further illustrative example of the present invention, an onlinemeeting, collaboration and/or desktop sharing service, such as thehosted service of GoToMeeting.com, WebEx.com, or LiveMeeting.com may usethe techniques of the present invention in one or more combinations. Thehost service may use a gateway 340, and the techniques of illustrativemethod 260 to facilitate a peer-to-peer connection between a firstcomputing device of a meeting presenter and a second computing device ofa meeting attendee. The computing devices of the meeting presenter andattendees may download via the host service the remote access client120, or any portions thereof. Once the meeting presenter and the meetingattendee establish a peer-to-peer connection, the peer computing devicesmay use any of the optimization techniques of the present invention tooptimize their communications, such as the MTU adjustment technique,client-side application aware technique, or the network disruptionshielding technique. Along with the peer-to-peer routing, theoptimization techniques of the present invention, will improve theperformance, efficiency and user experience of the online meeting,collaboration, or desktop sharing.

In yet a further aspect and in view of FIG. 2A, for example, the remoteaccess client 120 of the present invention can distribute Dynamic HostConfiguration Protocol (DHCP) IP addresses of the client 105 or thepublicly visible IP addresses to the telecommunication device 210 a-210b, such as either a hardware or software based VoIP telephone. Thegateway 340 of the present invention facilitates the discovery of thepublic IP addresses of the client, such as client 105 b illustrated inFIG. 2A. As such, the techniques of the present invention enablesprotocols that communicate their IP address over the protocol tocontinue to function.

Many alterations and modifications may be made by those having ordinaryskill in the art without departing from the spirit and scope of theinvention. Therefore, it must be expressly understood that theillustrated embodiments have been shown only for the purposes of exampleand should not be taken as limiting the invention, which is defined bythe following claims. These claims are to be read as including what theyset forth literally and also those equivalent elements which areinsubstantially different, even though not identical in other respectsto what is shown and described in the above illustrations.

1. A method for adjusting the maximum transmission unit of a securenetwork communication to reduce network fragmentation, the methodcomprising the steps of: (a) establishing a session between a firstcomputing device and a second computing device, the first computingdevice having a first network stack; (b) detecting, by the firstcomputing device, a network packet having an encrypted payload; (c)determining, by the first computing device, a setting for a maximumtransmission unit parameter of the first network stack to reduce themaximum transmission unit size by at least a size associated with theencrypted portion of the payload; and (d) altering the maximumtransmission unit parameter of the first network stack to the determinedsetting.
 2. The method of claim 1, comprising communicating the networkpacket via one of a secure socket layer or a transport layer securitytunnel to the second computing device.
 3. The method of claim 1, whereinthe payload comprises a real-time protocol.
 4. The method of claim 1,further comprising altering the maximum transmission unit parameter viaa network driver interface specification level mechanism of the firstnetwork stack
 5. The method of claim 1, further comprising determiningthe setting of the maximum transmission unit parameter dynamically persession between the first computing device and the second computingdevice.
 6. The method of claim 1, comprising establishing the sessionbetween the first computing device and the second computing device via agateway.
 7. The method of claim 1, communicating by the first computingdevice one of real-time voice, audio, or data to the second computingdevice via the payload of the network packet.
 8. The method of claim 1,comprising communicating a false acknowledgement of receipt of thenetwork packet to one of the first computing device or the secondcomputing device before communicating the network packet.
 9. The methodof claim 1, further comprising establishing the session between thefirst computing device and the second computing device via an agent ofthe first computing device.
 10. The method of claim 9, comprisingcommunicating, by the agent, via an IOCTL application programminginterface to the first network stack to alter the maximum transmissionunit parameter to the determined setting.
 11. A system for adjusting themaximum transmission unit of a secure network communication to reducenetwork fragmentation, the system comprising: a means for establishing asession between a first computing device and a second computing device,the first computing device having a first network stack; a means fordetecting, by the first computing device, a network packet having anencrypted payload; a means for determining, by the first computingdevice, a setting for a maximum transmission unit parameter of the firstnetwork stack to reduce the maximum transmission unit size by at least asize associated with the encrypted portion of the payload; and a meansfor altering the maximum transmission unit parameter of the firstnetwork stack to the determined setting.
 12. The system of claim 11,comprising a means for communicating the network packet via one of asecure socket layer or a transport layer security tunnel to the secondcomputing device.
 13. The system of claim 11, wherein the payloadcomprises a real-time protocol.
 14. The system of claim 11, wherein thepayload comprises a representation of one of real-time voice, audio, ordata.
 15. The system of claim 11, further comprising a means foraltering the maximum transmission unit parameter of the first computingdevice via a network driver interface specification level mechanism ofthe first network stack
 16. The system of claim 11, further comprising ameans for determining the setting of the maximum transmission unitparameter dynamically per session between the first computing device andthe second computing device.
 17. The system of claim 11, comprising ameans for establishing the session between the first computing deviceand the second computing device via a gateway.
 18. The system of claim11, comprising a means for communicating by the first computing deviceone of real-time voice, audio, or data to the second computing devicevia the payload of the network packet.
 19. The system of claim 11,comprising a means for communicating a false acknowledgement of receiptof the network packet to one of the first computing device or the secondcomputing device before communicating the network packet.
 20. The systemof claim 11, wherein the network packet comprises a lossless protocolpacket.
 21. The system of claim 20, wherein the lossless protocol packetcomprises a transport control protocol.
 22. The system of claim 11,wherein the payload comprises a lossy protocol packet.
 23. The system ofclaim 22, wherein the lossy protocol packet comprises a user datagramprotocol.
 24. The system of claim 11, comprising an agent of the firstcomputing device for establishing the session between the firstcomputing device and the second computing device.
 25. The system ofclaim 24, wherein the agent communicates via an IOCTL applicationprogramming interface to the first network stack to alter the maximumtransmission unit parameter to the determined setting.